From the back of the package:
The odds are tremendous. You are fighting for your life and IT seems to be playing games with you. You're being squeezed by impassable defense shields. The obstacle shields are growing. Intelligent plasma fireballs threaten to disintegrate your existence. The only hope for your survival is to beat IT. That requires expert evasive maneuvering and dead-sure shooting. They sure didn't mention anything about IT in Cadet training.
Death Trap is an innovative space showdown with a touch of strategy. Unlike most shootouts, the enemy defenses build as you inflict damage. You develop a strategy to control where the defenses are built. Time is of the essence. You must be effective in your actions.