Use WASD and the arrow keys to drive the UFOs of candy-loving aliens to the lollipop. Avoid the black things. Use space to reset. Pressing 1, 2, 3, 4, or 5 changes the difficulty. The only way you can reset the difficulty is by finishing the race.
I tweaked the later difficulties and made them terrifying. *EDIT* Difficulty 6 is still possible. And for some reason, now you have to press space twice to reset.