Keep the spaceship up in the air as long as possible. Press space to start. (Not sure why, but you may need to press it twice) Move the mouse and click to aim and fire the cannon. WASD to move the spaceship. If you are suffering lag, turn the "Lag" slider to 1 to disable particles. Turbo mode will kill you immediately. You lose when the ship hits the edge, a rocket hits the ship, or you shoot yourself.
This game will often have a fair amount of lag. I'll try and fix that later. Thanks to @nparekh for small enhancements.
