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

 By Cyberman