Eerie creatures launch an assault against Moon Station Tranquillity. Use your Laser Cannon to blast them - or they'll devastate Earth! Waves of demons circle the lunar surface, bombarding Earth's last outpost. Resist their dive bombing blitz. Fire into their ranks and shatter their raid.

Then go on the offensive! Take off from the surface of the moon and combat the demon base. Eliminate the flickering shield. Repel the suicide patrollers that come hurtling your way. Place one shot directly through the revolving window and into the fiery core. The demon base will disintegrate. But the battle goes on!