When the game has loaded, and the title screens are flipping about, type "DAVID BROADHURST WANTS TO CHEAT", or "AMIGADAVIDBROADHURSTWANTSTOCHEAT" or "AMIGA DAVID BROADHURST WANTS TO CHEAT" (I don't know if you need to insert the spaces - sorry). As you hit the last 'T', the message "CHEAT MODE ACTIVE - HELLO TO CAROL..." should flash on the screen. Now your energy and fuel will go down slowly, making it much easier to complete levels.

Type in "DAVID BROADHURST WANTS TO CHEAT" and things start to happen, like infinite lives, etc. On the Amiga put one extra space between the second and third words.