It's Tetris as we all remember it. Drop different shaped blocks into the container, and fit them together to form a horizontal line, and the line disappears. Your job is to keep going as long as possible by clearing the container of blocks.

This will be the first time on a Game Boy System that 4 players can play multiplayer Tetris, which is much the same as the original Tetris, only that when you clear a line of blocks, the line(s) appear in another players screen.