Unlock Wolfenstein 3D:
Beat the single player Campaign mode to unlock Wolfenstein 3D.
Multi-player mode: Airstrike
A lieutenant can call in an airstrike by pressing “Zoom”, then pulling the trigger on where you want the bombs to drop. There is a ten second delay.
Multi-player mode: Medical kit
A medic can help his teammates by switching to the medical kit. Press [R] to drop it
Aliens reference:
The main menu music for the game has been taken directly from James Cameron