For me, it has to be Alien: Colonial Marines as it’s terrible due to inconsistent frame rate (moments the game ran smooth and times where lag was insane, even with the best hardware). Both player & enemy AI is crap since the combat wasn’t even that immersive plus Xenomorph AI isn’t as intimidating due to it being poorly implemented.
Since you reminded me and the lighten things up, the Alien 3 game was really quite good and sure beat the film.