OK, I know it's almost four years old now (Four? Four years? Really?! This was the last game I bought - what have I been doing all this time?) but **** me if this isn't not only one of the best Aliens spinoffs of all time, but also one of the best survival horror games of all time.
Atmospheric? Check. Nerve wracking? Check. I literally can't play the game for more than half an hour without having to take a break. It is intense. The xenomorph's AI and behaviour means that almost every playthrough and encounter will pan out differently. This isn't a pattern recognition stealth game, this is a seat of your pants and wing it stealth game. And it is troll-tastic.
The game was criticised by the mainstream reviewers on release, but it really is a cult classic.