I really like the concept here! Especially the idea of having the bubbles merge together again to make it more difficult to cruise through a level. I'd be curious to see how your game would play differently if the either 1) the controls were tweaked so you had more control over the player (accel/decel) and/or 2) you could store up more energy at once. I often got right up to 8 or 9 but would be out of shots and need to start over. Thanks for making and sharing your game!