Game: Fold It

Fold It is a game that helps science. Instead of having a great amount of resources destined to fold proteins, they let players around the world do that. With so many players competing to fold proteins, predictions can be made of the shape certain proteins will take. Also, players could end up designing proteins that might just be helpful to cure diseases.

In this game, each level is a "puzzle" which consists on a protein that you have to fold. There are several rules that you can follow to increase your score, for example, the more compact the protein, the better score you get.

The game is quite complex but the tutorials introduce each concept quite nicely. By the end of all the tutorial levels, you'll be able to tackle puzzles with real protein shapes and compete with other people around the world for the best scores.

What I liked about the game:
  • The tutorial levels introduce the game mechanics really well.
  • The game helps scientists find patterns in protein folding, which will eventually lead to understanding diseases and body functions.
  • The game gives you constant feedback and doesn't penalize mistakes so you can easily improve your protein folding techniques.

What I didn't like about the game:
  • Because camera movement and protein movement is performed with the same mouse button (depending on where you click) sometimes I ended up moving the protein instead of the camera, effectively destroying everything I had accomplished (The game comes with an undo command, but still it would be nice to have a different button or combination of buttons to move the camera).
  • Even though the tutorials are excellent, it takes a lot of time to get used to the game once you decide to try regular puzzles.

University of Washington (2009) Fold It [http://fold.it/portal/]

Game: Warning Forever

Although this game is not a serious game, it has a really interesting gameplay mechanic.

Warning Forever is a Top-Down Shooter game which consists on killing a boss in each level to proceed. The catch is that the boss gets progressively more difficult in each level and it will evolve depending on how you killed the last one.

If you keep killing the boss from the same spot over and over, it will grow arms on that place to make it harder to kill from that spot, or it might begin turning around as to force you to attack from a position you are least comfortable with.

If a certain weapon kills you, it is probable that further iterations of the boss will contain more of that particular type of weapon.

You can change your attack angle and make your shots narrower or wider so you can vary your strategy through each level.

The varying nature of the game, along with the need to see how the boss will evolve makes this game quite addicting.

What I liked about the game:
  • Evolving bosses make this game a different experience each time you play.
  • High scores encourage gamers to replay the game and reach further levels.
  • Easy to learn gameplay makes it easy to pick it up.

What I didn't like about the game:
  • Sometimes it's not clear how the boss will evolve, most of the time is trial and error.
  • Once you figure out how the game works, it's possible to force the boss to evolve how you want, instead of the boss evolving to counter attack your strategies.

Hikoza T Ohkubo (2009) Warning Forever [http://www18.big.or.jp/~hikoza/Prod/dlcount.cgi?product=wf]

Article: Proof of Learning

Proof of Learning: Assessment in Serious Games
David Michael, Sande Chen [2005]

This article explains why it is not enough for a game to say that "it teaches" and leave it at that, but to include, like every other tool of education, a way of testing that the player actually learned something.

When a computer is used to test a student, what comes to mind are long sequences of multiple-choice questions (MCQs), which makes this the easiest choice for assessment in serious games. Sadly, MCQs are not always the best choice (I might go as far as to say that they are probably the worst choice), mostly because even if they are good to measure memorization and retention of facts, they fail at evaluating if the student is following a process correctly and also, during a game, this kind of assessment will be percieved as boring.

So, how can someone do a correct and useful assessment in the context of a serious game?

Currently, there are three main types of assessment that are used in serious games:
  • Completion Assessment (The player completed the lesson?)
  • In-Process Assessment (How did the player completed the lesson?)
  • Teacher Evaluation (Does the teacher think the student understands the material?)

1) Completion Assessment

Translated to Serious Games, this could be if the student completed the game. The problem with this is that the player could have cheated or exploited holes in the system (which, as the article states, is something honored and rewarded between gamers, but not so between students). It's important to know whether the student learned the material or just learned the game and how to beat it.

2) In-Process Assessment

In Serious Games, this can be done by logging and tracking information while the student plays the game. For example, the time required to complete the lesson, the number of mistakes made, etc. Depending on the material that is intended to be learned, different kinds of information will need to be stored and different actions will need to be taken depending on them.

3) Teacher Evaluation

It's hard for a game to replace a teacher, so the game has to include tools to assist teachers in their evaluation, which can be homework control, grade tracking, reporting, etc. One example can be the inclusion of an 'Observer Mode' where the teacher and other students can actually watch the whole process.

As a game developer, implementing these methodologies can prove frustrating, because great care should be taken in maintaining the game fun. This is not an impossible task though, PIXELearning is a company that uses its own propietary engine to include pedagogy and assessment methodologies in their products.

One of these methodologies include a series of qualitative questions (I would assume at the end of a gaming session) such as: "You chose to do X. What was your basis for this decision? Why did you not choose Y?" So the teacher has more information available to judge how well the student really understands the material.

The article ends with a quote from Kevin Corti, former CEO at PIXELearning:

"[Serious games] will not grow as an industry unless the learning experience is definable, quantifiable and measurable. Assessment is the future of serious games".

Michael, David; Chen, Sande. (2005). Proof of Learning: Assessment In Serious Games. Retrieved March 31, 2011 from Gamasutra.com: www.gamasutra.com/view/feature/2433/proof_of_learning_assessment_in_.php

Paper: Evolution of Artificial Intelligence In Video Games

Evolution of Artificial Intelligence In Video Games: A Survey
Ken Mott [2009]

In this paper, Mott explains how AI has been implemented in different types of games and the future challenges it faces in modern games.

One of the first rough implementation of game AI ever made was in the game Pong. The opponent's paddle had to move up and down to be able to return the ball to the player. This is known as Tracking AI. In Pong, this can hardly be considered intelligent, but this is how it began.

Another implementation of AI was done in board games that had been made into video games, like Backgammon. The AI used in these games was called Path Finding or Searching and was used to determine the next move of the computer.

In games like Space Invaders, a different form of AI was introduced: Pattern AI, which is used to make the enemies appear more human like. In Space Invaders, this was used when an enemy ship drops down to hit the player. Instead of following a straight line, it would track the player and curved it's path.

In modern games, AI has gained a lot of interest. In First Person Shooters, game AI is used to make enemies seek cover or to create a sense of teamwork between them using Waypoint AI. Mott states that further improvement is needed in this genre because bots still charge into enemy filled areas and fail to find new ways to traverse the level different from the intended one.

In Real Time Strategy games, AI is controlled by scripting. The problem with this is that players will learn the patterns of the enemy and adapt to them. To counter this problem, Dynamic Scripting can be used or even Genetic Algorithms to change the AI patterns.

Finally in games like The Sims, different algorithms are used not to make them seem intelligent, but to create what is called Artificial Life, which is when programmers try to make characters seem more human-like, not just in their decisions, but also in their behavior.

As time goes by and computers let developers create more complex AI without sacrificing graphics, we'll see much better AI agents that enhance the gameplay experience of players around the world.

Mott, Ken. (2009) Evolution of Artificial Intelligence In Video Games: A Survey

Paper: Player Modeling for Intelligent Difficulty Adjustment

Player Modeling for Intelligent Difficulty Adjustment
Olana Missura and Thomas Gärner [2009]

Automatic difficulty adjustment is a topic of great interest in game development. It can keep the player in the best possible 'fun' state and in the case of serious games, it can keep the player in the best state for whatever the game's objective is.

In this paper, the authors compare static to dinamic difficulty adjustment and explain their algorithm to determine a good difficulty setting for any player.

Traditionally, games where the player can adjust the difficulty involve the player choosing one of several difficulties and the game changing accordingly. The problem with this approach is that it's difficult for a developer to model the correct difficulty for each level of the game, as some might be perceived as too easy or too hard, depending on the player. To refine this, the developer needs to spend a great amount of resources to thoroughly test the difficulty settings of the game. The aim of this paper is to ease this process by modelling different players and trying to classify each player to set the difficulty accordingly.

The method they use for this purpose is quite interesting and it can be used in any game as long as the correct measurments are captured. They created a simple game with three difficulty settings. Game testers played the game setting the difficulty as they saw fit. While they were playing the game, data like score and player health was being recorded. After enough testers played the game, a clustering algorithm was applied to the data and was able to make a classification of the behavior of a player related to the difficulty they were playing in. So now, the only thing that has to be done is to classify a new player as fast as possible in the beginning of the game to automatically set the difficulty of the game.

This method had some technical limitations, like not every game during the same length of time and not every game ending the same way, but the data can be normalized to solve this problem.

They concluded that intelligently adjusting the difficulty was significantly better than the traditional static difficulty adjustment method and to further add to the investigation, different clasification algorithms should be tested, like nerual networks or gaussian processes.

Missura, Olana; Gärtner, Thomas. (2009). Player Modelling for Intellignet Difficulty Adjustment

AI Topics on Educational Serious Game Development

Videogames have gained importance over the last few years, not only as entertainment products but also as a learning tools, advertising platforms and even as instruments for different types of scientific research. These are only a few of all the possible uses that videogames can have, but all of them can be grouped into a same category, which is called 'Serious Games'.

Focusing on the education genres of Serious Games I stumbled across several topics involving artificial intelligence that I found of great interest:

Natural Language Processing

Natural language applications that have been developed are far from perfect, but when correctly implemented, they can create experiences that can't be achieved with regular applications. One clear example is the game Façade, a game in which the player can play by saying what comes to his or her mind and the AI will make the characters react accordingly. Playing this game will reveal the advantages and disadvantages of such a broad gameplay mechanic: when the user plays the game as it was intended, the experience is enhanced to the point of being memorable, but when the player tries to 'game the game' (try to break it by writing nonsense or complex phrases), the AI tries as best as it can to give the player a reaction, but the game won't be able to react accordingly to each and every sentence thrown at it, which breaks the suspension of disbelief.

Another, more limited example is Scribblenauts series. In these games, the player has to solve different puzzle-like scenarios by using what he can find on said scenario. The catch is that the player can type anything up and that thing will materialize in front of his or her eyes. For example, if the objective is to reach an object that is too high, the player could type 'table' and 'chair', then place the chair above the table and jump on top of it to reach the object, or maybe another solution would be to type 'stairs' and see if the type of stairs that appear can be used. Crazier options include trucks, airplanes, atomic bombs, black holes, Santa Clause, Kraken, God, Chutlhu, and even meme characters like Longcat. Like Façade, this game won't be able to react to each and every word you throw at it, but because you use single words instead of complete sentences, the effect will last longer.

It would be interesting to see if natural language processing can be implemented in an education serious game to enhance the experience and improve the retention rate of the player.

Automatic Difficulty Adjustment

Being able to adjust the game's difficulty on-the-fly can be a great way to keep the player interested without the game becoming stale or too hard. In the case of a serious game focusing on education, this means keeping the player in the best possible learning state. There have been several attempts to do this, for example Watcharasatharpornpong proposed the use of genetic algorithms to automatically adjust the difficulty of a platformer game by generating levels that match the player's skill. Another example could be the game 'Warning Forever', a shooter in which the objective is to destroy the boss of the game in each level untill you die. The catch is that the boss learns from your previous actions and adapts accordingly in the following level, for example, if your strategy was to stay in the middle of the screen most of the time, it's probable that the next boss will turn around to force you to move from the center and change tactics.

It can also be interesting to see if this would be effective in an education-based serious game.

Expressive AI

Expressive AI is a term created by Michael Mateas which involves the AI making a game feel 'alive'. A simple example he provides is the famous game Pac-man. In this game, the ghosts' behavior make the player think that they are actually setting up traps but in fact, they are only following simple but really good thought out patterns. This effectively makes the game feel 'alive'.

The game Façade is also an example of a game Expressive AI because the characters really behave as expected creating the illusion that they indeed have feelings. This also makes the game fun, because it keeps the player interested and wanting to know how things will turn out, mostly because it's the player that's causing those reactions.

This is a broad topic that could find several implementations in an education-based serious game as a means to maintain the player engaged or as a means to improve the learning and retention rate of the player.

Educational games are perceived as 'boring', so creating an effective educational serious game that is perceived as a 'cool' game is quite a challenge, but with the correct implementation of several different techniques, it is possible to develop a fun game that engages players and at the same time, teaches them something without them noticing.

  • Watcharasatharpornpong, Nirach. Automatic Level Difficulty Adjustment in Platform Games Using Genetic Algorithm Based Methodology. (2009)
  • Mateas, M. "Expressive AI: Games and Artificial Intelligence", in Proceedings of International DiGRA Conference. (2003).
  • Wilcox, Bruce, Beyond Faade: Pattern Matching for Natural Language Applications. (2011)
  • Bellotti, F., Berta, R., & De Gloria, A. (2010). Designing Effective Serious Games: Opportunities and Challenges for Research. International Journal of Emerging Technologies in Learning, 22-35.
  • Iwatani, Toru. PacMan (1980)
  • ProceduralArts. Façade (2005)
  • 5th Cell. Scribblenauts (2009)
  • Ohkubo, Hikoza. Warning Forever (2005)


Conference: The Mobile Serious Games Conference

Out & About: The Mobile Serious Games Conference

Out & About is the first ever event dedicated to the creation and distribution of serious games on mobile platforms.

New platforms, digital distribution strategies, and robust installed bases in mobile phones, and mobile handheld consoles have created an environment that makes it far more possible to consider deployment of serious games in the mobile space.

Out & About offers a means to see a combination of pioneering mobile serious games from the recent years alongside a number of new developments happening on iPhone, Android, and Nintendo DSi. From ARGs, to pedometer powered adventures, Out & About will bring you up-to-speed on this exciting new area of the serious games field.

Go to the Mobile Serious Game Conference main page.

Game: Lightbot 2.0

Lightbot 2.0 is a small flash game in which you have to guide a robot through the environment to light up certain tiles. You will do so by programming certain behaviors into it.

Through the game, you can either move forward, turn right, turn left, jump or turn on the tile you're standing on. For this, you have a "main program" and two functions to work with. With this, you can create loops, recursion and conditionals to achieve your goal.

What I found interesting about this game, is that you can indirectly learn basic programming logic, even recursion, which is normally a somewhat confusing topic.

The following video shows the first levels of the game:

What I liked about the game:
  • Cool way to learn basic programming logic.
  • Seeing your program work and improving it with trial and error helps you get better quickly.
  • The tutorial explains the game mechanics really good.
  • The game allows user created levels, which extends its replay value.

What I didn't like about the game:
  • The GUI could be improved a little bit, sometimes modifying your program takes longer than it should.
  • Turn arrows can get confusing on certain situations.

Play the game here.
Coolio Niato (2010) Lightbot 2.0 [www.kongregate.com/games/Coolio_Niato/lighbot-2-0]

Book: What Video Games Have To Teach Us About Learning And Literacy

What Videogames Have To Teach Us About Learning And Literacy
James Paul Gee [2003]

Get the book on Amazon.com.
ISBN: 1-4039-6538-2

In this book, Gee explains how games can affect people and more importantly, how can they learn a great amount of stuff just by playing. Gee created a list of 36 learning principles and a thorough explanation of the cognitive processes involved in each of them, with research facts and personal experiences.

In one of the chapters of the book, Gee accurately explains how, if a game is well done, the gamer can have a special connection with his avatar representation. He uses the game Arcanum as an example. Gee says that in this game, he created a special connection with his female elf avatar so deep that that he transmitted his morals and values into his character to the point that he sometimes felt bad if things didn't turn well, feeling that he had 'let down' the character in the videogame.

This happened because there are three identities that work together when someone plays a game like this:
  • A virtual identity (one's identity as a virtual character in the game's world).
  • A real world identity (the non-virtual person playing the game).
  • A projective identity (the projection of one's values and desires into the virtual character).

These identities interact with each other thorught the game and as an example, he says that at any point, any of them can fail:

The virtual character can fail to defeat an enemy because the character was not strong enough to beat it. The real world person can fail to use the game controls effectivly, causing the virtual character to lose a fight that, according to the game's rules, should have won. And the projective identity can fail when the real player causes the virtual player to do something in the game that the real player feels the virtual player shouldn't have done.

Gee explains that this relates to one of the learning principles in his list, the "Identity Principle". This principle says:
"Learning involves taking on and playing with identities in such a way that the learner has real choices and ample opportunity to meditate on the relationship between new identities and old ones."

[This post will be updated if I find more interesting stuff]

Gee, J. P. (2003). What Video Games Have To Teach Us About Learning And Literacy (1st ed.). New York, United States: Palgrave Macmillian.

Paper: Beyond Façade

Beyond Façade: Pattern Matching for Natural Language Applications
Bruce Wilcox [2011]

Following my recent post about a cool game: Façade, it was brought to my attention this paper, which is an amazing explanation of the technology used for natural language recognition from A.L.I.C.E. to ChatScript, Façade being somewhere in the middle.

First, the author describes AIML (the technology used to create A.L.I.C.E.) and states all it's shortcomings. Specially, he says that AIML is extremely hard to read and to program, because of the intricate XML style and recursive pattern recognition. That doesn't mean that the system is bad, it's just hard to work with.

AIML example:

< 'category '>
<'pattern '> * I LOVE YOU < /pattern >
<'template '> Whatever < /template >
< /category>

(Ignore the ' . It's a patch to force blogger to show the tags)
The last code will match the string "I love you" if found at the end of the sentence.

Next, he speaks about Façade. With this games, their creators made a big improvement over the traditional AIML system. They implemented 'Discourse Acts'. This means that a reaction can be mapped to one of these acts instead of mapping it to a text, which allows the programmer to generalize many possible sentences into a single act.

The system used in the game was easier to work with than AIML, but it was still hard to read and do complex stuff.

Façade's system example:

(defrule positional_is
(template (tor am are is seem seems sound sounds look looks))
=> (assert (iIs ?startpos ?endpos)))

The last code defines the rules for the discourse act "praise".

Enter ChatScript, a system created by the author to make it easier to read and work with natural language processing. ChatScript aims to pattern-match on general meaning, so it tries to detect equivalence. With ChatScript, he managed to create a bot that fooled one of the four judges in the Loebner Competition into thinking it was human.

ChatScript example:

concept: ~meat (bacon ham beef meat flesh veal lamb chicken pork steak cow pig)
s: (I love ~meat) Do you really? I am a vegan.

The last code associates some words to the general term 'meat' and responds to sentence "I love *" where * is some kind of meat with the answer "Do you really? I am vegan".

ChatScript is a gigantic improvement in the natural language processing field and it can be used to create some interesting applications. ChatScript has many features like memory and conversation topics which are described in the original paper.

Wilcox, Bruce, (2011) Beyond Faade: Pattern Matching for Natural Language Applications. Retrieved March 17, 2011 from Gamasutra.com: www.gamasutra.com/view/feature/6305/beyond_façade_pattern_matching_.php?page=1

Game: GWAP

Gwap is a web site created by Carnegie Mellon University that tries to make computers smart. The site contains several games defined as GWAP (Games With A Purpose) that were designed to be fun but also to accomplish tasks that are easy for humans but difficult for computers, such as tagging photos, tagging songs, separating good looking pictures from bad looking ones, tagging videos, etc.

For example, the first game you can play in GWAP is called ESP. In this game, two players are shown a picture and both have to guess a word that the other player thinks that describes the picture (much like Google Labeler). This improves web image searches by generating descriptions of uncaptioned images.

Another game, Tag a Tune involves two players listening to a song. Players must decide by the one-word descriptions if the songs they are listening to are similar or different. This will allow complex music searches like "love songs".

One that caught my attention was Verbosity, in which one player helps the other one guess a specific word by describing as much as posible everything related to the word. This helps create a big amount of facts that artificial intelligence programs can use.

Every game will give you a score and that score will accumulate cross-games in you gwap score. With this, players can compete and advance their gwap level, which creates a fun environment and encourages people to keep playing (and helping computers get smarter).

What I liked about the game:
  • There's a great variety of minigames to play, keeping things interesting if you ever get bored by one of them.
  • This game will help the search engines give better results.
  • Short game spans allow players to play in their free time.
  • Global scores keeps players interested and encourages them to play more.

What I didn't like about the game:
  • Sometimes, when playing a game involving a picture, the game will present a file that has been removed, leaving you with a blank 'file not found' page which takes away all the fun.
  • It can become frustrating if the other player takes too long to answer or disconnects (it's not the game's fault, but it happens, and having to wait in a game that's supposed to be fast, can make you quit it entirely).

Check out the article that brought this to my attention.

Gwap (2011) Retrieved March 16, 2011 from gwap.com: www.gwap.com/gwap

Game: Fantastic Contraption

Fantastic Contraption is a really interesting game where you have to build your own machines or contraptions to make one pink ball reach the goal area.

You start building you machine in a blue area and you can place whatever you want as long as you keep your invention inside that blue area. The different pieces that you can are a wheel that turns left, a wheel that turns right, a neutral wheel that can move to either side, a wood rod and a 'water rod' (water rods can go through other rods, wood rods will collide with other wood rods.).

This game allows for an interesting trial and error experience in which you can get better and better by just playing and analyzing what's happening. Also, because of the game's nature, a single level can have practically unlimited solutions.

The following video can show how different users managed to solve the same level:

What I liked about the game:
  • A really well implemented trial and error style will make it easy for someone to improve their creations.
  • Players are encouraged to create amazing and convoluted contraptions just for the bragging rights of doing so, which is amazing for a game.
  • Players can create their own levels, which allows this game to always have new content.
  • The tutorial is well done because it introduces the game's mechanics slowly but interestingly enough.
What I didn't like about the game:
  • I thought this game was well thought out. The only minor gripe i had was that very rarely, some of the contraptions you create won't make sense but still will allow you to beat the level and you will be left wondering 'how did that just work out?'.
inXile entertainment (2011) Fantastic Contraption [http://www.fantasticcontraption.com]

Article: Making Hospitals Fun

Making Hospitals Fun: How can games improve the patient hospitalization experience
Erin Hoffman [2006]

This article explains how games are being used to bring entertainment and education for patients and visitors that go to the hospital. The author explains the following three projects:

The first project, created by the Entertainment Technology Center in Carnegie Mellon, was a frog-like shape kiosk that was placed in the waiting rooms with several activities for kids, the most popular of them being an interactive coloring book that allowed kids to create their own pictures and then 'play' them through an animation sequence.

This project created a fun environment for kids in the hospital's waiting room so they felt more comfortable while being there.

The second project, created by the Johns Hopkins University in conjunction with the Pediatric Rehabilitation Center in Mt. Washington, was aimed at kids with weight problems. The project involved the use of the Sony EyeToy and CatEye Fitness gamebikes to create a fun environment to do excercise. Also, that provided a safe place where all the kids could go and not be judged by their weight.

The last project, called HOPE (Hospital-based Online Pediatric Environment) was aimed at kids who were in isolated sociological situations in the hospital environment (kids that have to be in the hospital several days a week for several hours). The project involved the use of Xbox consoles and E-rated games so kids could play with each other, talk and connect socially. This made the isolated and frightening hospital experience less traumatic.

This article shows how videogames can really change lives in ways that you may never had thought. Some people say that videogames are a waste of time, the people involved in these projects can provide a different point of view.

Hoffman, Erin. (2006). Making Hospitals Fun: How can games improve the patient hospitalization experience? Retrieved March 16, 2001 from SeriousGamesSource.com: http://www.seriousgamessource.com/features/feature_110806_gfh4_2.php

Chosen Engine Justification

Deciding on a game engine to work on is one of the most important decisions that have to be made when developing a videogame. Several engines were considered for the development of our game, including Blender, Unity3D, Quest3D, Unreal, StudioDX and Torque. After taking into account their features and licensing fees, we narrowed down the list to Blender, Unity3D and Unreal

Although the three of them are really well designed game engines, we finally decided to work in Unity3D. Blender is free and has almost all the features that commercial game engines have, but Unity's ability to deploy the game on so many platforms and the fact that Blender's interface is not as user friendly as we would like, we had to eliminate Blender from the list. Unreal on the other hand was the most complete option of the lot, but for a small game developed by different people at different times, the learning curve could become an obstacle for future developers. We concluded that Unreal would be

Unity was chosen because it has one of the easiest user interfaces from the different engines available and its architecture allows fast prototyping as well as full blown game programming.

Unity has several features that will help us develop our game. It includes the PhisX physics engine which allows us to easily include physics in the game. Unity also allows easy audio managing with full 3D audio capabilities. Graphics-wise, Unity automatically optimizes it's scenes to obtain the best performance available.

This engine also includes easy to use editor which is mostly What-You-See-Is-What-You-Get and it allows programming in three different languages: Javascript, C# and a dialect of Python, Boo. This allows for different programmers who are comfortable in different programming languages to work together in the same project. Also, it allows the deployment of the game to be in either Windows, Mac or Web.

Serious game developers around the world have used Unity to create their games, some examples include: 'Timez Attack', a game that makes it easy for children to learn multiplications by repetition, 'WolfQuest', a game that educates players about wolves allowing them to play as one, and 'Global Conflicts', a game where players take the role of a journalist covering the Israel/Palestine conflict. These games have different styles, different gameplay mechanics and different target audiences, which is proof of the flexibility of Unity.

There are some differences between the free version and the Pro version of Unity, which includes some features like full screen effects, custom splash screens, and low level rendering access, but the free version has enough features for a small team to develop a high quality game.


[1] Petridis, P.; Dunwell, I.; de Freitas, S.; Panzoli, D.; , "An Engine Selection Methodology for High Fidelity Serious Games," Games and Virtual Worlds for Serious Applications (VS-GAMES), 2010 Second International Conference on , vol., no., pp.27-34, 25-26 March 2010

[2] Unity Technologies (2010). License Comparisons. Retrieved from http://unity3d.com/unity/licenses

[3] Unity Technologies (2010). Intelligent Games With Great Technology. Retrieved from http://unity3d.com/gallery/developer-profiles/serious-games

[4] Horta, Félix (2011). Motores de desarrollo serios. Retrieved from Agentes educativos para juegos serios:

[5] Valle, Jonathan (2011). Game Engines. Retrieved from Serious Games: An AI Approach:

Paper: The Suffering, A Game AI Case Study

The Suffering: A Game AI Case Study
Greg Alt [2004]

In this paper, the author explains how he developed the AI system for the game: The Suffering. Specifically, he talks about behavior, pathfinding and steering/collision.

The behaviors were programmed using a tree structure. Each behavior is a separate C++ class and are allocated when added by their parent behavior or deleted when removed by the parent. Behaviors at the top of the tree are abstrackt and generally use child behaviors to achieve subtasks. This system allows complex behavior and variety among different NPC (Non-Playing Characters) by allowing different behaviors at different levels in the hierarchy.

Unfortunately, this structure also made it extremely hard for the designers to manage different actions, for example, allowing two NPC's of the same type to have a different behavior, required a programmer to add a parameter to the parent behavior and made the code more complicated.

Pathfinding was done with A* and cleared using string-pulling. Some enemies can walk on the ceiling, so it had to be taken into account when creating a path. The system was able to tag edges as to denote special places like doors, ladders or ceiling/floor transitions. Also, edges could be tagged to exclude specific NPC types.

To avoid using a great amount of memory while searching for paths, they limited only one pathfinding per frame. Different requests must wait for future frames. For this system also, the designers found a hard time when using it, as they spent many hours setting up and debugging a movement graph for small levels.

Finally, the steering behaviors used in the game included: Arrival, Evade, Wander, ObstacleAvoidance, UnalignedCollisionAvoidance, Containment, Separation and Flanking, which allowed NPC's to approach enemies from the side or behind. Each behavior outputs an acceleration vector to the low-level movement system. NPC's are moved an animated based on this.

The author concludes that modularity is essential for faster development, as it results in less bugs and increased functionality. Also, he says that the AI system was hard to use by the designers, but it could be solved with a better interface and level editor.

Alt, Greg (2004). The Suffering: A Game AI Case Study

Game: Façade

Façade is an interactive storytelling game. In Façade, your friends (a married couple) invite you to their new apartment. Everything starts up nice, but as the game progresses, discussions arise and you have the power to help them save or break their marriage.

What you can do while playing Façade is walk, grab stuff, perform a limited amount of actions on certain objects and the most important action of all: talk. You can write anything and the game will react (most of the time) accordingly.

The great thing about Façade is that you can try different approaches each time you play it and you will surely get a different experience, even the conversation tree can go in a different direction from play to play.

The AI will advance the story depending on what the developers refer to 'moment-by-moment' interactions, which makes the flow of the conversation to look natural.

I played Façade several times. In one time, I was able to discover the root of their problems and had a happy ending. Another time, I tried to flirt with one of them, which caused a lot of awkward situations. One time I was being so annoying that they kicked me out of their apartment. As you can see, there are many different possibilites for each time you play.

This game is an interesting experiment in which you can explore social interactions, but more importantly, is a good example of game AI being used to create compelling characters and interesting game flow.

What I liked about the game:
  • Lots of conversation branches and the ability to say anything increases the replay value of the game.
  • The characters react surprisingly well to most of the things you can say. The reactions even change depending on where you are standing in the room.
  • The game's an interesting example of AI being used for character and story development.

What I didn't like about the game:
  • Because of the nature of the game, you will be inevitably tempted to 'game the game' by throwing the most awkward phrases you can think of, and the characters won't react to many of them, which dissipates the illusion of intelligent characters.
  • Sometimes, characters will walk through walls and furniture, destroying the otherwise well crafted suspension of disbelief.

Visit Façade's main site or download the game here.
ProceduralArts (2005). Façade [www.interactivestory.net/download/]

Paper: Expressive AI

Expressive AI: Games and Artificial Intelligence
Michael Mateas [2003]

In this paper, the author explains that the use of AI in games should be considered an interdisciplinary practice instead of just a "purely technical", concept that he calls "expressive AI".

Michael says that game AI should create a sense of aliveness, that there is an entity living within the computer that cares about the player's actions. For example, in a first person shooter, the player can easily interpret that the enemies want to kill him while avoiding being killed. In 'The Sims', each sim responds to new objects placed in the house, altering its behavior accordingly.

An interesting example that is given in this paper is Pac-Man, where the behavior of the ghosts is critical to understanding the game because they define the primary action of the game. The ghosts have the perfect combination of behaviors to make the game enjoyable and to make them feel alive. If all four ghosts were always trailing behind you, the game would be extremely easy. If they were always setting up traps and cornering you, the game would be extremely difficult. To solve this, the creator of the game decided to give each ghost different action patterns: the red ghost chases Pacman all the time, the pink ghost is fast and moves a little bit randomly, the blue one escapes from Pacman until he approaches the ghost enough for it to start chasing him, and the orange ghost is slow and moves randomly.

The simple algorithms of the ghost AI create a rich and unpredictable behavior that can even make the player believe that sometimes, the ghosts are actually setting up traps.

With this example, the author clarifies that AI is essential when discussing the design of the game.

Based on this premise, he continues to explain the game he has been working on: Façade (a first-person interactive drama). This game incorporates a great amount of game AI in it's game design, including natural language understanding to provide a moment-by-moment interaction while developing the story's arc (complication, crisis, climax and resolution).

Finally, the author concludes that the concept of traditional AI is good but not enough for a game, whatever the specific task of the AI, the important thing to remember is that it is always performing: entertaining, frightening, and amazing the player, that's why game AI should be carefully analyzed, it is of interest not only to the AI programmer, but also to the artists and game designers involved.

Mateas, M. "Expressive AI: Games and Artificial Intelligence", in Proceedings of International DiGRA Conference, 2003.

Paper: Learning In The Wild

Learning In The Wild: What Wolfquest Taught Developers and Game Players
David Schaller, Kate Goldman, Grant Spickelmier, Steven Allison-Bunell, Jessica Koepfler [2009]

In this paper, the authors explain their experience developing Wolfquest, which is a serious game about wolves.

It's interesting to see that they used several learning principles from the book "What Video Games Have To Teach Us About Learning and Literacy" (James Paul Gee) and integrated them into the different gameplay mechanics that a player can do in their game. These principles are reflected in the way people play and their research shows that they were successful as players really became interested in wolves.

WolfQuest involves three components: The game, the on-line community and the national network. They made the on-line community an important part of the game as it allows players to share experiences with wolves and nature inside and outside the game, as well as exchanging tips and strategies to improve their gaming experience. Moreover, the game's impact is expanded by a network of zoos and institutions involved in wolf education (they help extend the reach of the project).

Their research showed that after playing the game, people really improved their knowledge about wolves and actually became interested in doing wolf-related activities (visit a zoo to see wolves, talk to friends about wolves, read books about wolves, etc).

The game developers had some unexpected issues that I found quite interesting. They concluded that 3D games are actually very hard to make, with everything from textures and shaders to artificial intelligence and simulation. They even went 40% over their $275,000 game development budget.

They also found that the suspension of disbelief was hard to achieve. Everything had to react naturally, the environments had to look reasonably well and any mistake, even small ones, could break the illusion.

Finally, and something that really caught my attention, was that they found that once you release your game, it's the player's game, not yours. There's a high chance that players will play the game and use it in ways that you never forsaw or intended, and you have to understand that.

Of course, they found out a bunch of other stuff that should help anyone making a serious game (or any kind of game, for that matter) for which this paper also deserves a read, paying special attention to the "Learning from WolfQuest" section.

Schaller, D. et al., Learning In The Wild: What Wolfquest Taught Developers and Game Players. In J. Trant and D. Bearman (eds). Museums and the Web 2009: Proceedings. Toronto: Archives & Museum Informatics. Published March 31, 2009. Consulted March 8, 2011. http://www.archimuse.com/mw2009/papers/schaller/schaller.html


Game: WolfQuest

WolfQuest was created by the Minesota Zoo and Eduweb and it's a game that lets players experience what is it like to be a wolf. It was designed to provide enough scientific accuracy so players could actually learn several things about wolves, like how they interact with each other, how they hunt or how they raise a family. Their research has shown that the game has actually succeeded in both, teaching people about wolves and creating interest in wolves in general among them.

The game has a single player mode and a multiplayer mode. In single player mode, you can create your own wolf and you are left in the middle of the wild to survive. The game uses a sandbox approach, you can basically do whatever you want and experiment with different actions, and this helps the learning process because it allows players to fail without punishing them a lot. When interacting with other wolves, this actually encourages players expermientation with different actions and looking at the other wolf's reactions.

I didn't play the multiplayer section of the game, but I could assume that it's better than the single player because you can interact with other people, planning hunting tactics with other players should be better than trying to hunt on your own.

Also, this game relies heavily on the on-line community. They deliberately didn't explain many things in the game so they encourage on-line interaction with other people in youtube and their forums to exchange knowledge and strategies. I'm not particularly fond of this approach, but it can work if used correctly.

What I liked about the game:
  • You can customize your avatar, choosing any gender with different colors and traits. This lets players connect more easily with the game.
  • The player learns about wolves because it is required to behave like one to progress: hunting must be done, territory must be marked, pups must be taken care of and interesting interactions like 'establishing who is boss' are also necessary to progress.
  • The game keeps a good balance of realism and fantasy, such that most of what you can do is an acurrate representation of what a real wolf can do.
  • The social aspect of the game is cool and encourages players to talk to other people about the game and wolves in general, creating interest in the topic.

What I didn't like about the game:
  • The music gets extremely repetitive after a few minutes of play.
  • I understand why they decided to let some parts of the game unexplained, but for someone that is not interested in investing time on the online community, a simple in-game guidance could've been appreciated. This includes presenting the instructions in-game instead of presenting them in text windows and keyboard diagrams.
  • I experienced a game-braking glitch in which the camera got stuck just after interacting with another wolf and I was unable to move. I had to reset the game.

Minesota Zoo, Eduweb (2010). WolfQuest [http://www.wolfquest.org/downloads.php]

Game: Timez Attack

Timez Attack is game developed by Big Brains. It is a great advancement in games used for education, because it includes several elements from traditional games to complement the learning experience, for example, likable characters, diverse environments and interesting action sequences.

The game mainly requires you to solve multiplications. Solving multiplications serves the purpose of what could be considered a 'context sensitive button' i.e. pressing a button on a controller changes the action depending on the current context of the game character. In this case, solving a multiplication can open a door, kill an enemy, move a platform, etc.

I remember being a kid and playing a Sesame Street videogame on my NES which also had some kind of 'in-your-face' math operations (moments where it's obvious that you're solving a math question), but I remember having a lot of fun playing it. This time, however, I was having a hard time keeping interest in the game. I believe the main reason for this is that I'm nowhere near the target audience, but I still found that the excessive use of the 'in-your-face' multiplication questions interrupted the flow of the game, not as much as to break it, but that can sometimes become annoying.

Nevertheless, this is still an interesting game concept and can prove quite useful as a learning tool.

What I liked about the game:
  • The game includes lesson reviews to see the student's progress. This really helps teachers and parents understand which topics have been mastered and which haven't.
  • The 'retention module' is excellent to ensure the mastery of the content. There is no risk of forget
  • The characters and evironments are fun. This is a great improvement over the traditional pencil and paper learning experience.
  • It can truly be a fun experience for kids.

What I didn't like about the game:
  • The game's main mechanic relies on the learning by repetition. While it's an effective methodology, in videogames, repetition can be counterproductive.
  • The game's educational content is presented 'in-your-face'. Almost all the time, there is a gigantic multiplication written on a wall/box/enemy that you have to solve. It would be cool if this could have been a little more subtle.
  • Sometimes, too many math operations can interrupt the flow of the game.

Big Brainz (2011). Timez Attack. [http://www.bigbrainz.com/Download.html]