Results from Game Design Challenge: One Button

By staff [06.26.08]

 In a recent Game Design Challenge, you were tasked with designing a one-button FPS game. There was a lively discussion on the forum about what exactly constituted a one-button game, and why they are significant to game players with limited mobility.

The challenge came from Brandon Sheffield, senior editor of Game Developer magazine, who, in conjunction with Jill Duffy (editor of this site), decided which submissions were the strongest.

After reading dozens of submissions, it became clear that the challenge was really about inventing a simple game mechanic. Several readers evaded simplicity and toyed with the idea of using button presses like Morse code. Others developed a complex system of single, double, and triple button presses, as well as hold-and-release schemes, to create multiple functions for the one button. The problem with many of these ideas, aside from having to memorize an elaborate system, is that they create lag time between player input and on-screen reaction.

If the game mechanic part was the challenge, the creative part of the assignment fell to how people would interpret "first-person shooter."

Apparently "FPS" just screams for zombies. Rhythm games were also popular starting points. But the big winner was rail shooters, which received resounding consensus as a foundation for a one-button FPS game.

Best Entries
Evgueni Dozov, ENJMIN, The Graduate School of Games and Interactive Media, France, Inertia & Recoil (see page 2)
In Evgueni Dozov's multiplayer game, players have one action, shooting, which has two effects: firing the weapon and moving the player backward. Each time a player shoots, she experiences an exaggerated recoil that's so strong, it propels her backward.

Evgueni adds a slight bit of chance, too, in that it is difficult to control how much spin a player experiences during the recoil (players have some control over spin, but not much accuracy). The goal of the game is to kill other players, who are also shooting and scooting around, while trying to master this slightly randomized movement scheme.

I hope Evgueni mocks up a prototype of this game. It's so simple and seems like it would be a real joy to play -- but we'll only know for sure if it's built and tested!

Connor Hogan, Death Crane
(see page 3)
Connor Hogan takes second place in this week's challenge for Death Crane on a Death Train. Imagine a train flying down a roller-coaster like track with a giant crane that is forever circling above an array of objects just waiting to be picked up and hurled at enemies. Hold the object too long, and the momentum will yank the train right off the track.

To critique the actual submission just a bit, Connor could have easily cut the first five sentences (see page 3) and gotten straight to the point. When you're tying to sell an idea (or get someone to read your resume or cover letter for that matter) those first few sentences matter the most. Make them count! Get to the point.

Jimmy Chang, civil engineering at Northwestern University, Death Puppet (see page 4)
Jimmy Chang's game is a wonderful take on cooperative play. Up to nine players can play, and each person controls an isolated motion of a gun-toting puppet. Players have to coordinate their movements as best they can to move through the world. When too few players are available, AI is used in their place.

The questionable aspect of this game is its repeatability and how new players will be introduced to the game. As a player becomes more adept at the game, she'll want to play with other equally experienced players and may feel frustrated partnering up with newcomers. If Chang wanted to write a full design document of Death Puppet, he might need to find a way to use the game's design to balance differently skilled players, for example, by configuring a test round that would ensure the most skilled player be the one who controls the gunfire, not a motion.

Honorable Mentions
Mark Sivak, graduate student at Northeastern University, Point and Shoot Nature Photography (see page 5)
We liked the idea of a nature safari game (though similar games already exist) and thought it would work well as a one-button game. Brandon Sheffield (one of the judges for this Game Design Challenge) pointed out that choosing paths versus shooting could get confusing.

Eelke Folmer, One-Switch Games, (see page 6)
We got busted by Eelke Folmer.

Says Brandon Sheffield: "Eelke Folmer should maybe be disqualified since his game is what made me think of this challenge in the first place! Ha! Not his fault really. This one is pretty good because it's already made and it works."

Evgueni Dozov, ENJMIN, The Graduate School of Games and Interactive Media, France
Inertia & Recoil

Inertia & Recoil is a multiplayer-oriented FPS using only one button. The players fight in level arenas where their unique means of moving is firing their gun in the opposite direction. The physics of the game are somewhat biased, and the weapon's recoil is exaggerated to allow fast movement.

Game mechanics
Controls. The game is entirely controlled with the left mouse button. A button press initiates the rotation of the character in either clockwise or anti-clockwise direction. The button release fires a single round in the exact direction you are facing at that moment, sending the character backwards through recoil.

Maneuvering. The direction of rotation depends on the previous shots: odd-numbered shots make you turn clockwise, even-numbered shots turn anti-clockwise. Once that aspect is mastered, a player can use it to move in a snake-like pattern.

Goals and rewards. The goal of the game is to kill the other players. To help you on your way, different bonuses are located in the level, granting you extra recoil, extra turn speed, etc. In addition, every player killed drops a bonus as well. But can you make that u-turn fast enough to get there before the others?

Single-player version. The game proposes a single player mode, where the player can get familiar with the controls. This mode uses a puzzle approach to teach different aspects of the game - maneuvering between obstacles, accelerating through repeated shots, scouting an area before moving there...

Platform and Audience

Inertia & Recoil is a PC game played online. It can be adapted to any other platform, as long as it has at least one button on its associated controller.

Due to the limited control scheme, the game isn't targeted at usual FPS players, but rather at casual players looking for a fun and tactical game experience with friends.

Unique Fun Points
Simple controls, countless possibilities. The combination of shooting and moving allows you to accomplish many things with a single action. But it also has drawbacks -- dodge quickly or aim well? Your choice matters!

Tension. With every shot, you're thrust towards the unknown. The FPS view never lets you know for sure what it is you're getting into!

Connor Hogan, Death Crane
And evil government has taken over your country. You are part of a resistance movement. You finally have your chance to strike back, as a weeklong magnetic storm strikes the planet.

All radar and communications are down. You and your resistance buddies plan to take advantage of this and strike a blow into the heart of the evil empire. You have a Death Train. The only weapon your Death Train possesses is a Death Crane.

The magnetic storm prevents the enemy from using airplanes and artillery to bomb the train (and they don't want to destroy the tracks, as they use them, so they won't plant mines), and they can't radio others to warn them of the incoming Death Train. You must make your way to the enemy's evil fortress, laying waste to helicopters, tanks, and other over-the-top mecha (think games like Raiden), enemy trains, and cities, while riding on complex, convoluted, over-the-top roller coaster-inspired railroad tracks.

The Game Mechanic
You control the Death Crane from a first-person perspective. You spend most of your time throwing things, but first, you must pick something up. Your resistance buddies have brought a bunch of stuff to throw on the train. The Death Crane will position itself over the item to be picked up, but the Death Claw will swing around. You must hit your single button with expert timing to drop it down and grab the item you will throw.

After you have grabbed and item, the Death Crane will start to spin (the camera will shift slightly, giving you a better perspective). You must hit your single button with expert timing to release the Death Claw and throw the item at your intend target. If you wait too long, the momentum of the swinging object will become too great and the Death Train will tip over.

After throwing an item, you have to grab another item to throw. There are also bonus levels in which the Death Crane has a traditional wrecking ball. The Death Crane will spin counter-clockwise automatically, and when the single button is pressed, it will spin clockwise.

The Platform
The PC is an obvious choice, but it could likely be ported to the Xbox 360 and PlayStation 3, enabling the wonton destruction to take place on large HD TVs.

Target Audience
The target audience is anyone who thinks a wrecking ball-touting crane ridding a train through a city, or a crane throwing cars, rocks, wrecking balls, and anything else it can lift off the back of a train into giant robots, helicopters, tanks, other Death Trains, and general over-the-top military machines is cool. In short: everyone.

Why the Game Will be Addictively Fun
My game will be addictively fun because it is not a defined game dumbed-down for an audience capable of only hitting one button, but would attract all types of gamers. Also, it involves a fun mechanic, and destroying things.

Jimmy Chang, civil engineer, Northwestern University, Death Puppet
A team shooter at its core, players are put in control of a death-dealing puppet, with the catch being that each player controls one of the puppet's actions independent of the other players. Thus, one player may be tasked with firing the puppet's gun, while another is responsible for moving the puppet forward.

Platform and audience: PC or Xbox Live; for people who don't take FPSs all that seriously.

Game Mechanic
The game's multiplayer component is absolutely integral to its appeal and must be played online. Players group in teams of one or more, for a maximum of nine players on each team. In order of decreasing importance, the actions that a player can be assigned to are:

In the event a slot cannot be filled by a human player, the computer will automatically control that component of the puppet. Additionally, each of the starred actions can be assigned to a single player; for example, holding the button will move the puppet forward until the player presses the button twice in quick succession, whereupon holding the button will move the puppet backward thereafter. Except for shooting, actions can be split into two separate actions to accommodate each additional player over five.

Why It's Awesome
It's a casual social shooter where you're fighting against your opponents just as much as you're struggling to coordinate the puppet with your team. Spastic, drunken puppetry ensues.

Honorable Mention
Mark Sivak, graduate student at Northeastern University, Point and Shoot Nature Photography
The player is a nature photographer who specializes in natural disasters (tornadoes, earthquakes, hurricanes, etc.). The player and his or her crew (AI controlled) travel around the world. The crew drives, and the player shoots pictures and movies.

The Game Mechanic
This would basically be a rail shooter from a game mechanics standpoint. The player can choose the path in which the crew drives [using single click (yes) or double click (no) responses to questions] and then uses the single button to shoot photos and record short videos.

Choosing the right path gives better possible shots, and better shots earn more money. The player can use the money to upgrade his or her camera so that it is more stable, has better focus, and better range. Favorite photos can be placed online to be judged in a weekly contest for the best photo. Also, there is an achievement system for getting action shots or shots of certain natural disasters.

This game has a very simple control scheme and it is a photography game so graphics should be the focus when choosing a platform. Playing it on a TV by using a console or even the TV remote is the best platform choice.

Target Audience
The game is non-violent and would appeal to a wide audience. Because the game is played on a TV the whole family could get involved by helping to choose paths and taking turns using the camera.

Why It's Addictively Fun
The player has the ability to plan the route beforehand and makes changes to it on the fly, giving the idea of control even with a single button input. Enabling the player to post his or her best and favorite photos and movies online gives the game a collection and competition aspect that many players love. Also, the excitement of being in the middle of a natural disaster would be great on larger TVs with great sound.

Honorable Mention
Eelke Folmer (for his existing games)
Rather than proposing a unique new game concept specifically focused on a one switch game play, we believe it is possible that any existing game can be turned into a one switch game with the right amount of automation and application of scan mechanisms. We therefore outline the technical details of a mechanism that in our opinion preserves as much as possible the original gameplay of a first person shooter while still being binary switch accessible. (e.g., no holding buttons). See my website ( ) for a number of popular game genres we turned into a one switch versions including Monkey Ball and Mario Kart without significantly changing any of the underlying game play.

We already developed a one switch mod for the popular FPS Half-Life 2 death match called Gordon's trigger finger ( Implementation is fairly easy as the player is put on top of an enemy bot and the player is only able to fire the gun, aiming and moving is done automatically.

This solution works particularly well for the multiplayer death match version as players usually move around randomly so there is no real need for being able to move, and players are attacking each other all the time so your ability to respond needs to be fast. In essence it is a rail-shooter except the player does not move on a rail. The only thing that needs to be available in the map is a set of waypoints used for pathfinding when the bot is in attack mode.

We play our mod in spectator mode, which automatically interpolates between frames preventing nausea caused by the jittery movements of a bot. This mechanism is also agnostic to level design, nothing has to be hardcoded in any of the levels that you want to play, as all the interaction is embedded in the bot, we also constantly press the action/open door to open doors or activate switches but we disable the sound as it is annoying.

Unfortunately our implementation cannot be used to play the single player version, as that involves activities like moving to specific places, climbing ladders, jumping and crawling, so here we propose a mechanism that will allow our current mod to be used with the single player version where being able to move and jump and crawl is desired using an adaptive scan mechanism that has two different modes:

1) Attack mode; if you spot an enemy or you get hit by an enemy you automatically go into attack mode where the switch is bound to the fire key of your current weapon. The bot moves and automatically aims at enemies it is up to you to fire at the right time.

2) Navigation mode: when not under attack; you automatically go into this mode when not hit by enemies for 20 seconds. We now use a scanning mechanism called rotate and extend that we developed for a one-switch client for Second Life (see An arrow will be visible at your feet which rotates from left to right, pressing the switch determines a direction and now the arrow will start to grow. When you press the switch again the arrow will become fixed and you will start moving towards the top of the arrow. Jumping, climbing ladders and crawling can be accessed by not pressing the switch when the arrow grows. The arrow will grow to a certain extent and then start to shrink again. When it is back at your feet it will briefly go up for a second (climb ladder) arc forward (run jump) and down (crawl).

By adaptively switching between modes we don't have the problem of having to respond fast which is only the case when under attack or when attacking. The proposed mechanism is far from perfect but we hope to implement this soon in our existing mod and gain more experiences.

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