For a truly intense Aliens fix, try out this flash port someone made on Newgrounds of the old Aliens board game. You basically play out the action-packed scenes from the movie, and the game uses the music and sound effects from the film as well, to further enhance the atmosphere. It's quite a challenge, as well!
I have some trouble trying to run this game. After I downloaded it I ran the one that said something like "Alien Breed New" and the screen just went black, some interesting music started to play but an error about some screend driver going nuts popped out and made my PC crash. Is this a common bug for Windows XP computers?