X-COM INTERCEPTOR (MicroProse)
During the game, press 'Ctrl' and 'e' simultaneously to activate the cheat mode. You'll hear a double chime. You won't see a text box, but you can now type the following codes: 
Canttouchthis	God in combat
Knowitall	All research
Fillerup	Unlimited flight range
Payday	Gain $10m