It has flaws, yes: the game certainly overstays its welcome, and there are some cheap-as-hell encounters by the end. But it is absolutely one of the best-imagined and executed visions of a film universe in video game form, and well worth the $9-15 it's currently going for.So while humans and androids are learnable but still interesting, the alien is something else. It feels sentient and autonomous. It feels organic and unpredictable. It feels less like some strings of code reacting to other strings of code and more like an active and independent agent doing whatever it wants. Which is where the game's most wonderful emergent behaviour arises from: walking through this room might be fine, as the alien is all the way over there; but it might also be impossible as the alien is hanging out in an air vent right in the middle of it. The game doesn't know, and it can't help you. It's almost like a computer virus in the software. It does what it want. Within certain constraints, of course, but it ultimately feels like the designers made this digital beast then let it loose. This is what makes it so terrifying: that knowledge that it is unpredictable and not leashed to the designer. It really could be anywhere. Some sections will be more scripted than others, but you never really know which ones. At any time the alien might be autonomous. You, player, are not the only active, intentional agent in this game. That is terrifying.