Tetris as we know it uses seven buttons: move left, move right, soft drop, hard drop, rotate left, rotate right, hold. Some older games would have only four: move left, move right, hard drop, rotate left. But the disability community is promoting "switch gaming", or video gaming that needs only one push button per player: Introduction by oneswitch.org Guide by BBC Ouch! Gamasutra article How would the tetromino game or other similar puzzle games (Dr. Mario, Puyo, Lumines) be played with one button?
Perhaps some sort of morse-code for the controls? Tetris can be played with one finger, as demonstrated on the iPod, but that requires something more complex than a single button.
I supposed you could have a disability mode that goes like this: During ARE, the game accepts a string of button presses that represent the final rotation state that you would like: 1 press - No rotation 2 press - rotate ccw 3 press - rotate cw 4 press - rotate 180 after a 1 second delay of no button presses, the game listens for more button presses that represent the column of the piece 1 press - column 1 2 press - column 2 3 press - column 3 etc... the game would then spawn the piece in the rotated state, and drop it into the column specified. This wouldn't allow things like sliding under pieces or wallkicks, but many poor tetris clones don't support those anyway. The number of button presses could be reduced by using long presses versus short presses, as Rosti suggested with morse code.
Japanese cell phone Flash games are full of those single-button games due to the Flash Lite implementation's inability to capture directional keys. The fact that it cannot distinguish between short presses and long holdings of the button makes design considerations even worse, pretty much boiling everything down to "watch moving objects to wait for the timing and press." One example of single-button games I thought was actually some good and had depth to it is Nanaca Crash. (Disregarding the anime theme for a moment) the game quickly and constantly changes through multiple contexts, and has a good mix of predictability and randomness to allow players to build strategies.
Back on topic; If I were to make Tetris to work with one button, I'd make it like this: Additionally, maybe time pressure can be added by having the piece hard drop when no input has been given for a set period of time. The player would be able to counter this by moving the piece back and forth. This would probably be the equivalent of 20G and infinite lockdown. Or, to make it harder, the delay could be set to a specific value that the player can't extend (entry reset lockdown). Not sure how to do step reset, though.
Watch my one-handed TGM1 Gm video on youtube and you'll see that you barely have to move your hand. My point is that reducing Tetris to one button is making it work for the worst possible handicap that can still theoretically play tetris. If I was handicapped, I would want to play something that made full use of my potential abilities. Even if I only had feet I would be insulted by a one button game. Everyone can play a one button game, but only the smallest audience will want to. When's the last time you checked out a children's book from the library? Just about everyone can read those...
No gravity. prompt orientation: button functions as clockwise rotation pause prompt move left or right: press once for left, press nothing for right pause prompt movement: button acts as left or right. pause hard drop? limited, but functional.
The current piece rotates around repeatedly. Press the button to stop it rotating. It then moves sideways until you release the button, at which point it drops.
Oh yeah, how could I forget it - NS-TOWER. Addictive as hell, along with its two-button sibling, NS-SHAFT.
Also, why has nobody mentioned Uo Poko? It's a clear-levels-time-attack puzzle game not unlike Puzzle Bobble. 1 button; hold it down to pull back the plunger. It gets quite intuitive and fast paced after a while.
my idea: piece can be rotated during entry delay. but: each button press resets entry delay. no input -> piece starts to fall. important here is to visualise entry delay - for example with a shrinking bar (as i did in cubestorm alpha) if falling: either lardarses idea: hold down, piece moves and cycles through all horizontal positions. release button, piece stops in current column and hard drops. OR tap button to move left and cycle through all columns OR - for progamers (should be faster than tapping ) 0 presses: middle column (5) 1 presses: - column 4 2 presses: - column 6 3 presses: - column 3 .. so the piece zigzags through all columns. though no hard drop possible...
my idea which would apply to speed would be holding the button, and having the piece shift from colom 1 to 2, then 3 untill you let go, [with the ...."pac man" effect of wrapping to the other side incase you miss] then pause, then hold for rotate, if not, tap it once, then like a double click for a hard drop. you couldn't make t-spins. but i would like to see an idea that you COULD make t-spins with one button.
move phase delay idea: during entry delay: rotate. entry delay resets with each button press. new: move phase delay: each button press moves piece to left (with wrap around), and resets "move phase delay". if no button was pressed till move phase delay is over, dropping starts. if during drop button is pressed --> hard drop. additionally: during lock delay we can again enable rotate (cw, ccw alternating), so we could have T- and other spins.
