Tetris DX

Not to be confused with Tetris Deluxe, a game released for western mobile phones.

Tetris DX was a Game Boy Color game as an enhancement of Nintendo's original Game Boy Tetris, with two added gameplay modes (Ultra, lasting 3 minutes; and Vs. CPU, a match against the computer), a profile/save feature, and color graphics on Game Boy Color and above. In addition, the game's rotation system had a glitch which lets a player move any tetromino except O upward by holding the direction against a wall while rotating in the opposite direction.