One or multi player tile matching puzzle game.

The player controls pairs of blocks (gems) that drop into a pit-like playfield. gems can only be eliminated by coming into contact with a Crash Gem of the same color, which eliminates all adjacent gems of that color, setting up the potential for huge chain reactions.

As gems are eliminated, "garbage blocks" called Counter Gems will drop into the opponent's playfield; these will eventually become normal gems, but only after some time and until that time they cannot be eliminated by normal means.

The game continues until one player's field reaches the top of its fourth column (which is where all new gems first appear). That player is the loser.