ColorTetris is a little more than just Tetris. It also includes Pentix, a popular variation of Tetris that is more complicated and more interesting, ColorTetris, SuperTetris. There are also many block sets to play. You can use your own sound effects if you like, but the preset sounds will not disturb you while you play. The Background grid can also be changed to your liking. Multiplayer mode (via LAN or internet).
Software Library
