Left/Right arrow keys to turn. Up/Down arrow keys to speed up or slow down Space to shoot. Complete all the levels before your time runs out or your health runs out. Health resets at each level but fuel doesn't. A tip if you're stuck is to fly far away quickly, then turn around and slow down and start shooting. Level 1 is one enemy plane, level 2 is 2 enemies, level 3 is 3 enemies and level 4 is a big helicopter.
All crappy art except for the explosion and helicopter by me. All code by me. Helicopter sound from Helicopter Combat The helicopter fight is a bit buggy.