Ivan Garde’s game design studies online notebook

and also an animator’s portifolio (hopefully)

What’s a Feedback Loop? dezembro 16, 2008

Filed under: Studies — ivangarde @ 12:24 pm
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There’s multiple ways to look at games and frame them, one way is to study them as closed formal systems. Surely they are not entirely closed, since I don’t believe we can think of human players as elements in a fully closed system, but lets just analyze the game rules for now and so, view them as closed systems.

In this kind of systems, the relation between the system’s elements can generate an emergent behavior, and it’s wildly spread (ok, not so wildly) and I do believe that a good game needs some level of emergence. Part of the fun is the ability the player has to alter the game world (the system) and watch how the game world reacts, how does it changes and affects all it’s elements towards the game’s goal, for that reason, the way that the elements in systems communicates with each other is crucial.

Within a game there are many systems that regulate the flow of play, in the form of the rules, dynamically changing and transforming game elements, as would say Salen and Zimmerman in Rules of Play. That’s where I want to get to, a very special sub system, a way of communication between the elements, the feedback loop.

The feedback loop is like an abstract tool you can use to generate some kind of behavior in your game, but what is it and how can it help you achieve what you intended for your game? Our subject is some sort of collection of sub-systems inside the formal structure of the game that senses the game state, analyse if the changes activate any given bias and then responds activating a controller that changes the game state, closing a loop of feedback information!

The schematic of a Feedback Loop structure

The schematic of a Feedback Loop structure

I think the best way to understand feedback loops is through examples, so lets look at this entry at the Team Fortress 2 official blog, here’s an excerpt

How do respawn waves work? Is my respawn time affected by my performance? Why do they exist at all?

Respawn waves occur on regular intervals, based on the map settings. Most of our maps use a 10 second respawn wave time. That 10 seconds is then modified by the map state, generally reduced for the team that controls the most capture points. (…)

So here we can see a feedback loop sub system in action at Team Fortress 2: There’s some control tool that reads a subset of the game state, in this case, the number of capture points each team has, there’s another system that analyses if this state is above some bias (which team control the most capture points) and finally a mechanism that apply a adjustment to some element in the game, in this case, reducing the team’s time to respawn. This change will end affecting the game state back by making the life of the winning team easier a bit, helping them and driving the game to a conclusion, as they keep the larger number of capture points, the team’s respwan time is kept reduced, or as said in the original post:

in TF2, the time you take to reborn after killed is dependent on the game state

in TF2, the time you take to reborn after killed is dependent on the game state

“They provide a reward for the team that’s doingwell, in that ifthey wipe out a significant amount of the enemy team they’re rewarded with a short grace period in which they can achieve objectives.”

Now that we understand what a feedback loop is, we should note that they can be divided into two categories:

  • Positive Feedback Loop: Encourages the system to exhibit ore and more extreme behavior by rewarding  the actions that drive the system out of stability, like the case in team fortress 2 where a team that’s already winning gets even further advantages.
  • Negative Feedback Loop: Those are stabilizing and bring the system to a fixed, steady state. A nice example is Mario Kart Wii, where the player that’s in first place never gets the best power ups from the “?” boxes while those player that are in the 2 last places always get power-ups that gives them a great boost, this mechanism prevents the player in first place to get too much ahead and the last positioned from being too far behind, which encourages a close and more competitive race.

In Mario Kart,the item you get depends on your place in the race, and they will most of the time, alter your place in the race.

In Mario Kart,the item you get depends on your place in the race, and they will most of the time, alter your place in the race.

Several boardgames use negative feedback loops to keep the player toe-to-toe with each other until the end. A fine example is Power Grid, a game about supplying cities with electricity, the first player to supply a certain number of cities is the winner but, every turn, the play order is changed so the players that supplies most cities are penalized in several ways, keeping the competition very tight until the conclusion.

A power Grid Board

A power Grid Board

The scholar Joris Dormans used Power Grid as a case of study for his Visualizing Game Dynamics and Emergent Gameplay article, in wich he proposes an UML model to describe the relation between elements in the game system, a model to analyze the emergent gameplay with a special notation to feedback loops, great article!

It’s important to notice that a game usually has more than one feedback loop, take the Power Grid example, the main structure of the game is a whole positive feedback loop: you buy plants to generate electricity and power up cities so they pay you, with this money you can buy more and better plants to power up more cities to get more money and so forth. This loop is the heart of the game and it pushes it towards a conclusion, but besides this one we can find the negative feedback loop aforementioned that keep the runway leaders at bay.

We can use the feedback loops as tools to achieve a certain tendency in a game:

  • Positive feedback loops usually destabilize the game, drive it to an end, magnifies early success
  • Negative feedback loops on the other hand stabilize the game, prolong it and magnifies later successes

But due to that kind of behavior, you need to have some care using this abstract tools in your game

A Chicken Cha Cha Cha game in progress

A Chicken Cha Cha Cha game in progress

  • The positive feedback loop can drive the game to a conclusion too early, or even worst, help one player get so far ahead that his/her opponents lose all hopes of catching the leader, like in the kids game Chicken Cha Cha Cha players move around in a circuit by memorizing a number of tiles, every time the player reveals a tile with the same illustration as the one in front of it’s chicken, that player can move one space and then play again. So as long as he/she keeps finding the correct tile (what can be done buy memorizing those that were opened early) he/she can keep playing until win, without giving a chance for the other players. Although it can be fun for the player in the a winning streak, it can be very frustrating for those that are only watching the other to play. Fighting games developed at the same time a kind of positive feedback loop and an answer to a problem like in chicken cha cha cha, at certain point, combo system were added to fighting games, it’s very rewarding for a player to land several blows in sequence, while keeping that sequence the opponent can’t defend (positive feedback loop), so, in theory, the first player to start a combo could keep it until defeating his opponent, but it never happened, because that fighting game designers always made this system limited: combos always end after a streak of 5 to 7 blows, even if the attacking player hadn’t missed anything, limiting thus, the effect of the combo positive feedback loop.
  • On the other hand, the presence of negative feedback loops in your design may make the players feel that are out of control, or feel they’re being penalised for a good performance. In the fourth incarnation of the famous RPG series, Elder’s Scroll Oblivion, Bethesda Software created a system in which every encounter in the game is always on par (levelwise) with the player’s character. Theoretically a very nice solution for creating a truly open world, without any kind of high level area in which the character can’t enter until reaching a specific level. We can think of this system as a negative feedback system, as the player keeps advancing his character, the creatures in the game’s world advance as well. It was designed to make every encounter worthwhile, to make the player feel challenged at each fight, but it had a side effect: due to this system, most of the players felt that they were not advancing anything, they couldn’t feel the power-curve, which is an important feature in RPG games. It was like “the same small goblin that killed me when I was level 1 is still giving me a headache now that I’m level 10, doesn’t matter if a level so”. The same system is in place in Fallout 3, but this time, it was highly tweaked so not all foes were evolving at the same rate as the player.

We are excluding form this discussion the players’  mind, which is always adapting and adjusting his plays during the game, we excluded the observer from the system, but even though, this kind of analysis is very useful for game design.
Now that we had this discussion I’ll try to identify feedback loops inside the games’ rules in the design analysis I plan to do in the next weeks.


Game Design Challenge: The Time Experiment #2 novembro 25, 2008

Filed under: Production — ivangarde @ 11:28 pm
Tags: , ,

At 11/12 GameCareerGuide launched another of their weekly game design challenges, which, in their words is:

“Design an experimental game concept that plays with the notion of time, and explain why it is worthwhile to conduct this experiment”

I feel it’s a great way to put my skills and studies to test, so I went off and cooked 2 ideas for the challenge which I’ll transcript here, the way I submitted them. Note that I followed their submission form.
Without further ados, here is the second attempt:

Entry #2

1.What is the name of your game, and please describe it (100 words max.)?
Game: Dystemporalia
The experiment is Real Time Strategy game, the twist is that it’s played in three instances for the same battlefield at the same time, each representing a different age of history. Whatever a player does in the prior ages affects the future ones (like erecting/razing buildings). The elements for RTS are present, but split among the ages: gathering in the past, combat in the present and technological advances in the future (affects past ages after discovering time travel). Each age has an independent win condition and the player is only required to meet one of them to win.

2.How is the core gameplay experimental? Give detail on the gameplay experiment you are performing. Why is this experiment important? What does it bring to games that is not already ubiquitous? (300 words max.)

RTS games that plays in more than one layer is not exactly a new thing, the concept of differentiation between ground and air combat is an example of this. Dragonshard already implemented a two layered battlefield, one for the RTS but the other was an action RPG. The proposition for this experiment is to create a new mechanic that will influence the relationships of cause-effect in a RTS. If you want something built in the future age you have to manage the gathering age layer, erect the building (and pre-requisites) at some of the appropriate ages, defend it in the present age to ripe it’s fruits in the future layer. But in my opinion the most important twist in this experiment is that each age/layer has it’s unique victory conditions. With this a player can pursue different strategies that will require different ways of looking at each age. I hope to achieve with this the sense of focusing in a strategy while having to keep an eye for in which age(s) are your opponent investing more playtime. The experiment should throw in more cause-effect relationships not currently found in RTS games, increasing the complexity of the player decision-making process.

I think the game would benefit form features like a “time travel”, a way that units and technology built in the future age can interact with the prior ages, augmenting the loop of cause-effect. I also would like to throw in the design feature that allow short-term advantages for a player at the cost of negative effects in future ages, like industry in the present age that improve the income generation from the resources gathered, but that would cause environmental disaster at the future age (even leading to a automatic losing condition).

3.How will you know whether the experiment is a success? What problems and limitations might arise? What do these limitations mean for future incarnations of this kind of gameplay? (300 words max.)

I fear that a design like this may become too overwhelming for the players, not due the relationship between the elements through the ages, but due the fact of managing 3 different layers at the same time. This game is actually target to be a multiplayer, so both opponents would face the same limitations.I believe that in a commercial implementation a great effort should be put in how to create the interface with the player, specilally the one that help him navigate trough the ages and see what’s happening in each one.

This experiment will be a success if the players do not feel overwhelmed to manage 3 layers of a RTS game simultaneously, and specially if the new relationships between units, buildings, technologies and resources spread among the ages allow for new strategies not currently beign used in the RTS games found in the market.


Game Design Challenge: The Time Experiment

Filed under: Production — ivangarde @ 11:24 pm
Tags: , ,

At 11/12 GameCareerGuide launched another of their weekly game design challenges, which, in their words is:

“Design an experimental game concept that plays with the notion of time, and explain why it is worthwhile to conduct this experiment”

I feel it’s a great way to put my skills and studies to test, so I went off and cooked 2 ideas for the challenge which I’ll transcript here, the way I submitted them. Note that I followed their submission form.
Without further ados, here is the first:

Entry #1

1.What is the name of your game, and please describe it (100 words max.)?
Game: Cut/Insert/A day in the life
This game presents a puzzle in the form of a narrative, in every level there’s a small story usually played by more than one character. It often presents an inconclusive or sad ending. For the characters there will be available a time track, in which the player can interact, it will be possible to cut samples of time and insert it elsewhere in the track. The player can also accelerate or slow down parts of the timeline, the number of available actions is limited. The goal is to create a new ending by manipulating (rearranging, accelerating) the characters actions.

2.How is the core gameplay experimental? Give detail on the gameplay experiment you are performing. Why is this experiment important? What does it bring to games that is not already ubiquitous? (300 words max.)

In many games the player is acting through the character, I wanted to create something where the actions are already chosen, a story is already there, but like “having second thoughts” the player can recreate the story not by acting in new ways, but by the”correct usage” of the same actions, like saying something to someone at the right time, not too late. So, the way a player can interact with the game is by manipulating the characters timeline and not controlling them directly, something I believe is not quite ubiquitous.
I believe this kind of interaction can be very interesting for the following reasons

  • It’s a nice way to toy with interactive narrative
  • coupled with a clever level design and the limited number of cut/inserts operations, it can also become a challenging puzzle
  • It can be made in line with Augusto Boal‘s theatrical poetics, the Theater of the Opressed. Boal’s poetics links with videogames have already been the subject of a thesis in Gonzalo Frasca’s Videogames of the Oppressed. I believe this kind of interaction can be a nice way to translate theatrical play into videogame, without becoming just a sand box for character interaction.
  • It can be implemented with intuitive controls to increase accessibility (low number of operations).

I hope to study with this experiment a direct translation of interactive narrative into a puzzle mechanics. the player should feel that each time manipulation for each character is relevant and should be chosen carefully (due to limitation of the operations) but at the same time it should allow the player to toy with the narrative, allowing the emergence of different stories within the interactions in a level.

3.How will you know whether the experiment is a success? What problems and limitations might arise? What do these limitations mean for future incarnations of this kind of gameplay? (300 words max.)

Let me start with the problems that might arise. I believe that the level creation to validate this experiment, and even to expand it into a full game is not trivial, if we want to meet the two premises: the game as a puzzle and the game system for emergent stories. I hope that with this system a player can get to similar (new) endings by messing with the timing of the character’s actions in different ways. The actions that character perform in the story must something novel, in order to help the player feel they’re playing with something new, I mean, avoiding classical “videogame actions” like jumping or hitting something.
The experiment will be a success if:

  • The player feels he can modify the story in many ways by altering the time in which the character’s action occur.
  • He feels it can generate new meanings and feelings for the new story.
  • At same time he knows that arriving at a certain state of the story will take carefully planning when manipulate the time of the actions.
  • The designers are able to create several levels that use this mechanics in a clever way for the puzzles while maintaining the possibility for level to generate different endings. Although I believe that the puzzle side of this equation is more important.

And even a bigger success if this mechanic could be integrated in different game styles, for instance, in a fighting game after the player and an opponent exchange some punches, blocks or combos, the player could pause, go back in time and rearrange the order of movements as a special skill or as a game unique feature.


Thoughts on the Design of “World of Goo”

Filed under: Analysis — ivangarde @ 7:32 pm
Tags: , ,

As one of the game design exercises I’m proposing myself, I’ll try to analyze the design of games in different styles. This time we’ll see a puzzle game that quite fast became big hit here in my place: World of Goo, form the indie dev

Crossing a gap at World of Goo

Crossing a gap at World of Goo

elopers 2DBoy.

In World of Goo you to help the charismatic goo balls to reach a pipe located in the level. You do so by using the intrinsic ability of the goo balls that is to unite with and grow some sort of lattice structure or trellis. That lattice is subjected to a very interesting set of physics, such as gravity, wind and the tension between the goo connections. The game has a “lemmings feel” due to the fact that you have to drive at least some number of goo balls to the pipe and, although they usually don’t run to suicide, every time you use a goo ball to grow the lattice you spend it and that’s one less to be saved (most of the time), making the game a bit more…could I say, strategic?

That’s basically how it plays and personally i think it’s a terrific game with lots of fun, but what are the design choices that make World of Goo such a good game?

First of all it’s nice to note that this game is based upon a specific toy: The lattice based physics. One of the two game authors, Kyle Gabler, created a prototype for the Experimental Gameplay Project back in 2006 if my memory serves me well called Tower of Goo and it was a big hit! So he and his partner Ron Carmel naturally took this toy and expanded for the World of Goo. Kyle Gabler has also several other very interesting prototypes in his profile at the Experimental Gameplay Project, all of them with a visual style that, at least for me, is greatly appealing!

A balance exercise
A balance exercise

Basically the puzzles are solved manipulating the growing lattice, sometimes you have to cross a gap or overcome a hazard and thus build a bridge, in others you have to reach a higher place, thus building a tower of goo. Each node (goo ball) in the lattice has a weight and each connection between the nodes has a tension, So everything you build in the game is subjected to a physical law, as said before, but this kind of system has some great advantages in the design space:

  • At first, the game has to tell the player only one rule: drag a goo ball with the mouse to attach it to the lattice. The rest, the way that the trellis will behave according gravity and the wind is easy to be infered by the player, since this kind of physical system behaves in a ubiquitous way for them. I mean, most of us have already made castles in the sand or played with some kind of Lego and we know that we can’t create a tower too high without a larger base. Since it’s natural to the player to understand the outcome of his/her actions in the system, it made up for a more engaging experience.
  • Even if you don’t understand the physical system, you promptly see the outcome of your actions, since each action affects the lattice right away, you build and the game answers you, a nice loop
  • The very action of building and playing with your structure is really fun, a toy per se. It’s so true that the game features a level for free goo-structure building, and people spends quite some time there.
  • A physical simulation system is naturally a system with emergent behavior, another important aspect of engaging games, although you have a clear objective in each level, the actions you perform to achieve the goal are far from scripted (opposite to many puzzle games, specially adventure games). Another great game that uses a physical system for puzzles that comes to my mind now is Half Life 2.
  • A reflection of this emergent behavior system is that each new goo ball introduced in the subsequent levels (the ones with new abilities) further increase the number possible outcomes for the structure. The final result of possible interactions and outcomes in the system is greater than the sum of it’s parts. Each new goo ability opens a lot of design space, such as the goo that inflates like a balloon, creating an upward force. In a moment of metalanguage, the “Sign Painter”, which is the game’s narrator, says something like “Across the distance they see lots of new goo species, the design possibilities are endless” 😀
  • To finish a level, the player has to bring only a certain number of goo balls to the pipe, a number usually small compared to the population of goo in a level. But each extra goo ball you bring to the pipe ends waiting for you at the free building area, so there’s is a purpose for getting more goo balls to the pipe. What i like about this is that it creates a variable difficult level, controlled in-game by the player. You can choose an easy play and just bring the minimum number to finish the level, or work hard to make every move worthwhile so you can bring a greater number of goo balls to the end.

I think World of Goo is a great game, not only with a very nice design, but the graphics and sound do a great job creating an almost idyllic place.


Puppies just wanna have fun outubro 30, 2008

Filed under: Studies — ivangarde @ 11:47 am
Tags: , , ,

In a study featured at MSNBC, psychology researchers have found that young male dogs playing with female pups will often let the females win, even if the males have a physical advantage.

Puppies playing

Young boy dogs often let the girls win — anything to keep the game going

I know this is not directly connected with game design, but I find it very interesting to notice that this kind of behavior occur in several species of animals (It has been documented before in red-necked wallabies, squirrel monkeys, hamadryas baboons and even us, humans).

Researchers suspect that for the dogs, the opportunity to play may be more important to them than winning. How many of us haven’t already done this? Letting a girlfriend win (without her knowledge, of course) just to make her more prone to play in the future or organising some game learning session with younger relatives where winning is the last of the concerns.

It looks like that to play is “per se” an important activity even in the animals life, but for the dogs at least, the act it’s not all devoid of practical implications. Playing with a female help the puppies to create a love connection which will help them mate later in life ( it’s know that in feral dog populations, female mate choice plays a role in male mating success) and the Young males use to play to learn more about the female puppies.

I believe that we follow a pattern rather similar, although studies implies that dogs may be less obsessed with winning than our closer relatives, the primates.


The inspiration for this blog’s URL outubro 15, 2008

Filed under: Random — ivangarde @ 2:34 am

Keep on rolling!


First things first!

Filed under: Random — ivangarde @ 2:11 am
Tags: ,

So I decided to start a new blog but, unlike my previous one, this has a specific goal: to serve as a notebook for my current game design studies. I find it very nice when people share their studies even when it’s somewhat idiosyncratic, and that motivated me to keep my recordings and analysis on this blog.

I’ll try to show here pieces of studies, design deconstructions of popular games for analysis and hopefully some personal creations but I must advise you, English is not my native language but I’ll do my best to keep this blog legible.

If you read until this line then I must tell you that I have a secret agenda here, I want to create a game design portfolio. Since the size of our game industry here in Brazil is close to nothing I think this is the better way to develop some game design skills.

Hope you all enjoy the blog and don’t hesitate to comment or curse like a sailor the posts you don’t like