Take control of a square and get the end, that's it! But it's not as easy as it would seem. The levels you go through are pixel-perfect mazes!
Tap the screen, or press space to jump. But make sure you time your jumps precisely! You can even hold your finger on the screen, or hold down space to jump repeatedly. (Or fly up, if you're in a rocket) Look out for spikes, if you touch them you will be returned to the beginning of the level. There are also many mutators to spice up the experience.