Bubble Bobble:

Play the classic Bubble Bobble game where your objective is to blow bubbles to kill monsters. You have to first trap the monsters into the bubbles then hit the bubbles to blow them away. Kill all the enemies in a level to progress to the next one. Do not let the monsters to touch you else you will lose lives. Use the arrow keys to move, press enter key to start the game, use ctrl key to select options, press X key to jump, and use Z key to blow bubbles.