Collect all the bubbles, but watch out for the spikes and enemies! Full instructions are in-game. If you want to turn off the menu background (it can lag slightly) change quality to low.
Left and Right key to change backgrounds while playing, control the golden bubble with the mouse and collect all the blue ones, then the purple one to finish the level. Watch out for the spikes!
Enemies are unlocked as you play, with moving spike balls at level 5ish, little yellow guys that chase you around also around level 5, then another new enemy at 15, and another at 20. There are 25 levels altogether, and have highscores at the end. Originally when you're score reached or went below 0 it was game over, but I decided to remove it to give the player a chance.