twinTris is a Tetris derivative for 1-2 players. 1 player mode is the basic Tetris as we know it, but it can be played upside down (when player 2 is playing alone). The 2 player mode is a special game mode, where two players play co-operatively. Player 1 drops his/her blocks from above while the other player's blocks "drop" from below. Together, they try to assemble lines to the center of the playing field.
The basic idea of Tetris is to get rid of the blocks falling from the top of the screen. This is done by assembling complete lines of blocks to the bottom of the playing area. The player can move and rotate the blocks. The player can also drop the block. In twinTris, there are two other game modes. In two player only the idea of the game is the same, but the game is "upside-down". In 2 player mode, both players try to accomplish this objective simultaneously, but instead of assembling the lines in the middle of the playing area.
| Action | Player 1 | Player 2 |
| Move block left | Left arrow | A |
| Move block right | Right arrow | D |
| Move block down/up | Down arrow | W |
| Rotate | Right Shift | Left Shift |
| Right CTRL | Left CTRL | |
| Drop block | Enter | Tab |
| Take screenshot | F10 | |
The scoring of twinTris is close to the scoring in the original Tetris. In Tetris, and twinTris, points are awarded for speed and the number of blocks destroyed. Destroying lines does not award any points. No bonuses/points are awarded for Tetrises (ie. destroying four lines at once). In two player mode, the same scoring rules apply, but there are penalties for missing a block (falling "through" the screen) and losing the game (aka. dying). At the end of a 2 player game, the points are balanced, so that the player with more points loses some of his/her points while the other player with less points gains some. This is to emphasis the co-operative playing.
| Option | Action |
| --nosound | No sounds |
| --fullscreen | Full screen game |
| --mescaline | Try =) |