Although it may be little more than a myth to some, the lesser spotted ludus modus singulus — also known as the “single switch game” in day-to-day discourse — is a very real and fairly common kind of game. It operates on just one rule: input must be limited to a single keystroke. No arrow keys. No mouse magic. Just a handy little button on your friendly neighbourhood keyboard or gamepad.

strangeThis kind of interactive entertainment has fascinated game developers since the beginning of existence itself, and oral traditions speak of a time long ago when such games ruled the earth, roving the vast plains and humid marshes of a much wilder planet. To this day they are still relatively untamed¬† by man, and only the most skilled — or foolish — of developers attempt to create them. But the rewards for demonstrating mastery over this genre are immense. Ask the creator of iPhone hit Canabalt if you have any doubts.

Nowadays, the average input device really spoils developers for choice. Keyboards are a sea of possible letters and numbers. Gamepads have thumbsticks, shoulder buttons and rocket-propelled grenade launchers up the wazoo. Even the humble Wiimote has quite a few input tricks at its disposal, especially when you consider the versatility of its motion sensor. But truth be told, not enough designers put that much thought into how players interact with their games: even when designing titles for something like a touch screen, too many devs try to force “many-button thinking” into a button-shy environment instead of forging new ground with the given platform’s unique restraints. I’ve seen it happen with cellphone games, iPhone prototypes and even mint dispensers, and the results can become rather… well, rotten. And rotten mints are just plain wrong.

One-switch games evolved as a tool to enable accessibility for disabled gamers, but they’re a damn useful exercise for developers in their own right. Offerings like Strange Attractors are excellent demonstrations of how versatile and interesting a project can become when given a one-button constraint, testing the developer’s ability to think in terms of context-sensitivity, emergent complexity and the various effects that any given environment can have on players. And sure, sometimes projects can be just plain fun (like the ever-delightful Dracula Cha Cha), but sometimes they’re also pretty astounding exercises in lateral thinking.

Dracula

An interesting analogy would be to compare good game development to physical fitness (possibly the first and last time this will ever happen). For some poor, untrained bugger, doing a few laps across the swimming pool could pose quite a challenge. But if you force them to swim across the Atlantic — eliminating the practical drowning possibility, of course — those couple of laps suddenly become a lot less intimidating. Placing developers into such a restrictive situation can inspire levels of creativity and modes of thinking that otherwise may not have emerged.

A demonstration of some interesting one-switch games can be found in the Gamma IV games showcase, a collection of more than 150 titles which have also been featured at this year’s Game Developers Conference in San Francisco.

Have you ever tried making a game with a weird and creative constraint? Throw in a comment below and tell the rest of us about it!