Guns were probably added to make the game more interesting. The actual film featured no weapons aside from pipes and other makeshift tools.
Game Over screen
The game over sequence of this game features a variation of Bill Paxton
's iconic "Game over, man!" ad-lib from the accompanying film's predecessor Aliens
. Since rights issues prevented Probe Software
from using the actual clip, a recreation was recorded by Paxton to play on the game over screen.