Worms Blast is a puzzle game similar in concept to Puzzle Bobble, with several important distinctions and gameplay features taken from Worms games. Instead of releasing and matching bubbles, the player has to color blocks on a hexagonal grid. Unlike most Bust-A-Move variants, the player character can move right and left, sailing in a boat. Various weapons, such as bazooka, grenades, dynamite, and others, can be used to fire at the blocks, coloring them on impact.
The gameplay involves hitting blocks that match the color of the missile fired, destroying them and any adjacent same-colored blocks. Differently-colored blocks will not be affected by shooting at them; however, if they are held solely by a group of blocks of the same color, they will fall into the water when that group disappears. Blocks with rainbows on them can count as any color.
The game features two main modes: Puzzle mode and single-player tournament mode with high scores. The action component is particularly noticeable in multiplayer mode, since the walls between areas will periodically open, allowing players to use this opportunity to shoot at each other's boats. There are also various multiplayer modes available.