In 1991, shortly after the original release by Demonware, DMI/Global Software got exclusive rights from the original publisher to redistribute the game.
 Distributed in Germany by Rushware and in Italy by Softel.
During the title screen type:
JUHU for unlimited lives.
BIGI to get 20 lives.
QUAK to get all extra equipment.
Additionally, leaving the title screen with left mouse & fire will give you 7 lives.