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What videogames can be made in four days with an unfamiliar game engine? Using a game engine developed at a previous IGJ, this year's group created 17 games focused on using the physics from the engine.

Justin Hall, Blogger

May 5, 2004

22 Min Read

What videogames can be made in four days with an unfamiliar game engine? Now in its third year, the Indie Game Jam works to energize innovation in videogames by giving two-dozen game designers a basic technical infrastructure and a short time frame to create a game. When an entire game development project is compressed into a weekend, experimentation is king and production values won't stand in the way of a good time.

In 2002, the first Indie Game Jam challenged fourteen game designer-programmers to design a game using just 100,000 sprites. Gleeful chaos ensued. The second Indie Game Jam used Zack Simpson's Shadow Garden engine: video projectors for display and webcams for input. These games explored human shadow as an interface; seventeen enthused jammers could be seen waving their arms and even grabbing and wrestling each other to make winning shadows.

At this year's Indie Game Jam, two-dozen programmers set out to find fun in the chaotic excitement of physics-based gameplay. With only a weekend to compose playable games using a bare-bones 2D physics engine, the participants found camaraderie, frustration, and a few nuggets of insight.

Previous Game Jams were held in "the barn," a rustic, waterfront, indie game development enclave in Oakland, California. This year the modest and stylish Washington Inn in downtown Oakland partitioned off a conference room: two dozen designer-programmers spent the weekend coding and playing games sandwiched between a meeting of government officials from Mexico and the hotel's formal dining room. The close confines and narrow ventilation demanded some open doors, giving the well-heeled diners next door a chance to peer over their wine glasses and gourmet Mediterranean plates directly into the workspaces of energetic game geeks.


A "skycam" view of the room from up on top of a table.

By its third year, the Indie Game Jam had developed a familiar rhythm--veteran participants met a few new faces amidst banks of computers and bundles of bright blue Ethernet cables. Through Girl Scout cookies, Doritos, and empty soda bottles, the largely male group mostly knew how to pace themselves; how to get their creativity flowing by playing with the tools and collaborating with their neighbors.

"Physics must be good for something besides ragdolls and exploding crates."

This year, the organizers intended to push more experimentation than normal. Independent game programmer Chris Hecker wrote in the initial invitation email: "We think it's a great time to do a Jam about physics in gameplay, since a lot of developers in the industry are trying to figure out how to integrate physics into their commercial games as more than just special effects, and we can explore that space and report the results."

This year's engine was a 2D physics simulator from Atman Binstock. Binstock developed the engine for a game during last year's Jam, where two players use their shadows to push jiggling objects through a 2D maze. Binstock's engine provided a shared framework to experiment with physical properties: a system for easily modifying objects, forces and constraints, and the chance to watch them interact.

During the first hours of the Game Jam, you could see people tossing geometric shapes around their screen, playing around to understand the parameters of the play space. Shortly they began constructing within that space--or working to enlarge it.

The 2D physics engine presented an immediate challenge. AI researcher Robin Hunicke arrived early to help set up, and she arrived ready to design: "I came up with some ideas before I had actually seen how the engine behaved, and then I got here, and my ideas weren't really compatible with the physics of the engine." Hunicke recounted her jam experience mid-way through: "So physics is a big word, it means a lot of things. You think, 'Oh, physics! The world has physics,' but the engine has physics that are not necessarily the same as the world. I wanted to do a game where you built shoes and then tested those shoes on different types of physical surfaces, but sadly the engine doesn't support the kinds of friction and the kinds of things that would make that easy to build." Playing around, Hunicke discovered that the "shoemerang" shoe movements she had rigged up onscreen made for a decent art program; she turned them instead into a spyro-graph drawing tool.

Level Deformation

Co-organizer Sean Barrett adapted Hunicke's footwear fascination into a seemingly simple platformer. Barrett's BootLooter centered around a tiny character roaming a post-apocalyptic shopping mall, searching for the last surviving pairs of designer pumps. The physics was involved as the tiny character had the ability to kick out the support beams and cause the level to fall to pieces--either promoting her objective, or at least creating some fun chaos. On the second night of the four-day Jam, Barrett reflected on chaos in 2D games: "The problem is that physics tends to make things chaotic. … Is that really antithetical to game design? Is the chaos introduced by physics bad? How can we leverage the chaos, or how can we make it non-chaotic?" Barrett adjusted his glasses and continued, "Maybe it's a new technique or tool that we can use for new things. How can we put physics into our games other than to just make them more realistic, what can we do that makes the gameplay more interesting?"

For interesting gameplay, there's always excessive violence. But Game Jam co-organizer Casey Muratori would take exception to that: describing his Stunt Hamster game, he protests "it's a game where you light hamsters on fire. But it's not gratuitous!" For Muratori, hamsters are a stand-in for flammable liquids, and much like Barrett's game, the gameplay lies in deforming the level. "The physics engine treats the hamsters kinda like a fluid. So you basically fire all these hamsters out of a cannon, and you pack them into different areas and then when you light them on fire, the gas that gets let out of that displaces the fluid very violently. So you can change the structure of the level because this organic fluid explosion allows you to push blocks over and do these cool things." Casey nods enthusiastically. His game emerged from play, and much public discourse of the abuse of rodents.

"You've got to have failures."

"It was a struggle to make a game that was a game, and not a physics simulation" reports veteran game industry programmer Ken Demarest. Like Hunicke, he arrived at the Jam with a fleshed-out game idea: "The design was this thing where you'd run around on a sort of platformer level. Which I figured would be good, because you'd have gravity in a platformer. And you would get guns that would let you melt the ceiling, heat it up, or melt the floor into a lava pool that would stop people from walking over it. Or take an ice gun and freeze the ceiling that was in the middle of melting down, right in place, or make a floor really brittle so when you dropped something heavy on it, it would bust." He smiles ruefully, "Absolutely 100% not doable in this physics system." Demarest went through two game ideas before cooking up a game about clearing snowflakes from over eyeballs in a confined space. It wasn't his initial vision for 2D physics, but he was an unabashed participant: "It was quite demoralizing for a while. But that's the nature of game experimentation. You've got to have failures. Or you're just not going to be able to truly innovate."


Ryan Ellis, artist, leaning back.

Like most of the game designer/programmers present, Demarest believes that gameplay innovation grows increasingly difficult as game budgets swell. Co-organizer Chris Hecker spoke lucidly to this topic the night before: "The Indie Game Jam we did to encourage innovation in the industry. The game industry at large has so much money at risk in every title now, because you have to hit it out of the park in order to make money. And to do that, you have to have these huge production values." Hecker sees this threatening the evolution of the medium: "For an art form like games that's so young, it's a little dangerous to be so risk-adverse so early, before we really know what we're doing, games-wise. Unless we think that the games, the genres, the gameplay mechanisms we have right now are all that we're going to have and we're just going to be polishing them for a long time." For Hecker and the other co-organizers, the Jam is a chance to skip commercial concerns and rapid-prototype new gameplay.

As it turns out, physics is one ripe area for innovation in game design. Doug Church sat in his white-stockinged feet in the corner of the Washington Inn conference room, offering commentary and the beginnings of a balance board game. He used the two thumb sticks to directly control each of the feet of a stick-figure, using a board to stay over a center rolling pin: "I wanted to do something where you had to use both joysticks at once and kinda try to do a sort of zenned out balancey kinda small moves kinda thing." Church paused his programming to meditate on the state of physics in gaming: "Most shipping games use physics for cosmetic output. It's often very cool--Max Payne 2 did some great physics stuff, with Havoc. Still you could essentially take it all out and you have the same game." Church sees an interesting future for physics in gameplay: "No one's really made it an integral part of player control, or of emergent elements of the game, where the player can interact, and I think that's a super-interesting place to be."

This year's Game Jam was a good chance to experiment with physics in gameplay, but 2D and 3D physics are a bit different. Still, he sees some value in these experiments, as Game Jam participants were forced to ask themselves--"I do think some of the things you think about here--like 'hey, physics causes these sorts of things, how do I put the player in a state where those sorts of things would lead to interesting results, how do I get more places where the physics pushes back' and makes me kinda go 'oo I could do this thing' and less places where it's like 'hey, those particles sure exploded pretty, good thing I'm running physics,' where the player really could care less, it could just be a pretty animation."


Unscripted Entertainment

While he's not a programmer, game writer Austin Grossman was perhaps the most vocal physics proponent at the Jam. "People don't realize how hard they have to work, to build an environment where they can't script things, they can't control things--they have to create a cool environment where players can make up activities for themselves and creatively solve problems." Grossman spoke as he worked to tune Chris Hecker's hopper game, designed around a small jumping figure who aims his leaps to climb a series of obstacles. Grossman was providing the obstacles. His belief in the open-endedness of physics-based gameplay conflicts somewhat with his work as a writer: "Physics tends to sit on the antithesis of traditional narrative, because it's so unscripted. You play around and cool emergent stuff comes out, but you totally can't predict it. The visceral toy-likeness of [a physics-based game] is a reflection of how interactive it is, and how far it is from our traditional ideas of narrative media. It plays much more like a sport than a movie."

Independent programmer consultant and Game Developer magazine contributor Jonathan Blow designed a spider's web simulation that was engaging to play from the start. Even without goals, building, cutting, and climbing around the web was fun, and this may have slowed its development: "It actually wastes a lot of time." Cocking his head, Blow continues, "I sorta veg out, like playtesting here a bit when I should be working on the next thing, because you know I'm just kinda walking around, hooking up some webs." If the fun was there from the start, the gameplay emerged later, over the course of the few days available; Blow later added scorekeeping with flies to capture and consume.

The Bare Minimum of Fun

Nearly all of the games at this year's Indie Game Jam used PlayStation2 Dual Shock controllers attached to desktops or personal laptops via USB. Thatcher Ulrich from Oddworld Inhabitants in San Luis Obispo developed a game featuring a pair of tippy robots equipped with oversized arms, which danced and boxed according to a very few button presses on the controller. The robots were hard to control exactly, but this imprecision made the button mashing fun. "I thought I was going to do a dancing game, a music game of some type, but a fighting game is easier to make," Thatcher says with a smile. His game emerged from fooling around with frustration: "I got pretty discouraged with the difficulty of making a physical game. So then I said I'm just going to play around, make some toy robots. And the toy robots worked pretty well. So that suggested the game." During the jam there were plenty of shouts from Thatcher's corner of the room; people enjoyed the wiggly robot whacking. Thatcher is a Game Jam veteran: "As someone who works in the game industry full time, I've done more game design in three weekends at the Indie Game Jam than I have in almost my entire career of game development. That's maybe a little bit of an exaggeration, but it's very educational, in terms of learning what goes into a game, and what the bare minimum is to make something fun."


Chris Carollo had four controllers attached to his laptop, all for plowing pigs!

Considering the length of time the designer-programmers had, and their total unfamiliarity with the engine, the fun that emerged from this year's Jam was remarkable.
Ranjit Bhatnagar from New York City's GameLab built a game where two players worked wasps to lift and coax a collection of small round foodstuffs into each of their own wasp pantries. Using fluttering wings to move small balls proved maddening and tantalizing, even without another wasp there to send the balls rolling out of your hole and into their own. Like Ulrich's game, the bugs were hard to control precisely, but this gave the game a jerky insects-in-flight feeling. Bhatnagar sat smiling as a string of opponents attempted to out-maneuver his wasp. He had co-designed the game with Michael Sweet, who was providing music and sounds at the Jam for the second year in a row.

Support Staff

Sweet was one of a number of artists and support staff who added a good amount of polish to these quickie game designs. After the first year when visitors were drafted into art duties, the Jam began recruiting a few skilled artists to work with the programmers during the weekend. This year, Ryan Ellis from OddWorld Inhabitants led a team of professional game industry visual artists, contributing to the games-in-progress. The team included Daniel Neuburger from Crystal Dynamics and Ocean Quigley from Maxis. "Front-load your art" the organizers repeated throughout the weekend, demonstrating the steadily increasing value of a finite number of artists available for just four days. While the games themselves used a 2D engine, Ellis and company contributed 3D and 2D models and backdrops for most of the games. A filmmaker Ryan Junell and I were on hand to document the Jam, both of us were drafted to make some quick and dirty visuals as well.

Some programmers provided their own polish. Chaim Gingold from Maxis placed two trees on the screen that swayed as players rocked their joysticks. His game was cooperative - fruit lay on the ground below the trees, and two players could only pick it all up if they swung in tandem together. With colorful sunburst designs and a team spirit, Gingold's game was the most positive human use of physics. And to boot, Gingold's game had a bright polished aesthetic. Demurring, Gingold explained, "The code looks like crap and the design is very simple." But his game looked--and played--like a weekend wedding between Nintendo and Apple.

Marc LeBlanc may have made the most gleefully sociopathic game this year. LeBlanc, who worked on Mind-Control's Oasis, wanted to use buoyancy to hold a game together, a game where heavy pieces were used to make light pieces sank. Writer Austin Grossman suggested LeBlanc consider floating corpses in the East River, and Sleep wit' da Fishes resulted. Each year at the Jam, one game features faces of the Indie Game Jammers; this year dead-looking programmers bobbed up and down in water as players dropped anvils in order to keep their buoyant bodies pinned to the bottom of the riverbed.

Charles Bloom from Oddworld Inhabitants built a two-player game: two ships orbiting a giant sucking black hole. This is Bloom's third year, and each year he made something multiplayer: "I came to realize that it's a lot more fun to have multiplayer games where you can interact with people at the Jam and play the games." Bloom's game had recognizable space-combat dynamics and a strong physics flavor: "It's a space shooting game where the idea is that you're not directly damaging your opponent, you're not shooting them with normal weapons at all. So you don't have health. You're just using the physics interactions to knock each other around." It takes a moment of adjustment, to play in the physics space instead of the shooting space: "Everything has realistic mass and momentum. And like one of the cool things is that you actually propel yourself by shooting masses out the back of the ship. And then you can collide with them too, once they are made. You have to use your thrust as part of your strategy, you can use it as a shield, you have to worry about colliding it, you actually get propelled as it piles up behind you and moves your ship around."

Chris Carollo from Ion Storm in Austin wanted to make a four-player game. He ended up with Pig Plow--a mess of slippery pigs scooting around a giant pen, policed by four plows eager to push pigs into their particular corner's gate. Carollo's game featured porcine physics power-ups, immediately reversing gravity or scattering pigs. He's a vegetarian, he explains, nodding with raised eyebrows, and these pigs are going to a happy place.

"Deepen into the right thumbstick of the PS2 controller"

Brian Sharp from Ion Storm developed a Yoga pose simulator using just a single analog thumbstick for control--left and right adjusted the lean, up and down adjusted the tension. Not content with his early stick-figure model, Sharp photographed and adapted the body parts of famous Yogi BKS Iyengar from his book "Light on Yoga." This was perhaps the most amusing design of the weekend, showing Iyengar struggling to keep his balance amidst the pages of his own book. Sharp described his game: "It's very cathartic! Actually, it's not cathartic at all. I have to be honest here, it's very tense. You're just sitting here balancing. As opposed to Thatcher's game, where you're just punching people. No punching." Sharp thinks for a minute: "Maybe it's meditative. If you get into it, just like any good Yoga pose, you can really deepen into the right thumbstick of the PS2 controller."


An early screenshot of Brian's Yoga game, in Trikonasana.

Independent programmer Atman Binstock had developed the engine, so much of his time was devoted to teaching and maintenance. He spoke some comforting words on the opening day: "Understanding the limitations of a physics engine is very hard, it takes a long time, I've been working with this code for two years and I still don't understand it." Between his duties Binstock still managed to polish up a physics game. His goal was to make a game world that moved in time with music, and a directly controlled character: a dancing shrimp had a head and tail that could latch on to objects, thereby propelling itself, or in-turn moving the object, deforming the level

Between rounds of testing and designing, small and large groups of programmers wandered through the streets of Oakland, enjoying Tin's Tea House, New World Vegetarian, or seven courses of beef at Le Cheval. The IGJ isn't simply about games, it's a sort of community of programmers. When it comes time to order pizza, co-organizer Chris Hecker calls out: "Okay guys--how hungry are you, on a scale of 0 to 1?" After tallying the empty bellies and desired slices, someone does the math and asks "Can we order 6.75 pizzas?"

"Oh my God, we're doomed; nothing works"

The Indie Game Jam is not easy. A short deadline to code PC games, using console controllers connected to a fleet of loaned computers, sharing an evolving codebase over a temporary network, and situated in a multiple-use facility presented a non-stop series of interruptions and demands for logistical and tech support. Add to that the pressure to make something fun out of an unfamiliar game engine, and it's a miracle that games come out playable, and participants come out eager to return.

Casey Muratori took a break from his exploration of flaming hamster physics to explain the virtues of the Jam. Sure anyone could work on a game alone in her free time. But: "There's the atmosphere with lots of really smart technical good game developers, to help you, to bounce ideas off of. Most of the best ideas in the thing I'm working on, were not mine, they were things that were stumbled upon or someone came by and said 'the problem with this game is that it doesn't have blah,' and they were totally right." It's not just programmers, however - there's a wide range of folks on hand: "We've got artists here, we've got musicians, there's people to do things that are not in my line of expertise. It's got a little microcosm of a game development house in it, enough that you can produce things that are much better than you could have done yourself."

Doug Church shares a bit of the uneasiness that leads up to the Jam: "Every year, a couple days before the event, it's like 'Oh my God, we're doomed; nothing works.' Then in practice, it's kinda true that nothing works, but you just throw everyone into the middle of the fire and things come out." After coming down off of the rush of dense game design and then sharing the game designs at the Game Developer's Conference's Experimental Gameplay Workshop, the organizers were loath to predict next year's Indie Game Jam. Opening the event at 11:30pm the first day, Chris Hecker joked "If you don't get it right this time, we're doing physics again next year!" You can visit www.indiegamejam.com, download games and source code, and decide for yourself how the experiments came out.


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About the Author(s)

Justin Hall


Justin Hall is the publisher of Links.net, a long-running site that was part of the first wave of personal web publishing. From 2007-2009, Hall was CEO of GameLayers, Inc. as they made a social game out of surfing the web. Prior to GameLayers, Hall worked as a Tokyo-based freelance journalist covering digital games and online culture. Hall recieved an MFA in Interactive Media from USC and a BA from Swarthmore College. Today Hall works as the Director of Culture & Communications at ngmoco:) / DeNA, a mobile entertainment company.

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