Get fired out of a canon, and stay in the air for as long as possible! Power-ups increase speed, rings give you points and rocks slow you down. The less speed you have, the harder it is to stay airbourne against gravity. Hitting the ground will end your flight.
SPACE - Aim and fire cannon
ARROWS - Move while in the air
Q - Toggle quality
W - Toggle foreground visibility
Rolling over endgame screenshots will expand them.