Keyboard Keys : Left & Right arrows or J & K to move the ship Space or K to fire or start a new game S to toggle sound on/off.
If keys don't work, click on the game to give it the focus.
The game : Playing the game is so simple it doesn't really warrant any explanation. Shoot at everything that moves and some of the things that don't. You'll soon learn which objects can be blown up and which ones just absorb the blasts. Avoid flying into anything that looks bulky and sticks out of the ground.