Bubble Bobble is the story of two humans, Bub and Bob who wander into the mysterious cave of monsters and magically turn into dinosaurs. The only way to transform back is to reach the end of the cave.
The gameplay involves each level being a single screen where enemies must be cleared from to progress. Players control one human at a time, jumping and collecting items for points such as fruit. Bub and Bob can also blow bubbles, which serve as platforms or traps for enemies. Trapped enemies turn into fruit when popped, while power-ups in the bubbles provide advantages like lightning that destroys enemies horizontally and water that drags everything down.
The NES version has extra stages, increasing the total number of stages to 112. The Sharp X68000 version includes a hidden minigame called Sybubblun, featuring 20 original difficult levels with a Syvalion theme.