Various cheats (submitted by Cyberman)
     Ingame  press '~' (pressing the 'Pause' key is useful), enter one
of the following codes and press 'Enter' for applying:

Code                    Effect
GiveMeAll               All following effects in the one mix
GiveMeFuel              Full fuel
MoreLives               Full lives
HealthMe                Full health
GiveMeInvulnerable      30 sec. invulnerability
GiveMeInvisibility      30 sec. invisibility
GiveMeAllAmmo           All guns, rockets, missiles, lasers,
                        plasma cannons and nuke