From C64CG website;

Instructions: This is for two players only (the Red player using port 1 and the Green player using port 2 respectively), using Left, Right and Fire to maneuver their planes. The basic objective of the game is to blast your opponents plane 21 times, whilst avoiding their attacks on yourself.

Further Controls

F1 - Toggle Colour Mode
F3 - Toggle Red Player Width
F5 - Toggle Green Player Width
F7 - Restart Game

Story: Return to a golden age of Gaming, with this frantic 2 player blast. Forget about realistic 3D graphics, and sampled sound and enjoy a shining example of when gameplay came first! Forget about Quake III, Blast that Plane is the next #1 multiplayer frag-fest!