This is in my opinion the Alien game we've been waiting for and as of now my Game of the Year.
Even without the Aliens unscripted AI this game would be brilliant with its well realised world that basically sits you in Ridley's idea for this universe buts its the Alien that sets this game apart from games like Outlast or Amnesia.

The issue most horror games have is predictable AI with set paths, while its still scary you can easily learn the enemies path and get into this repetition of waiting around a corner and then moving out when they've gone past, now while this does happen from time to time in Isolation with the other enemies (Androids and Humans), when you're dealing with the Alien there is no scripted path.
The fact that the Alien doesn't follow a path makes it so refreshing because theres no studying its path and then exploiting it, theres just you having to make quick decisions and using your available gadgets to improvise on the fly.
This is also another area games like Outlast and Amnesia have a problem with, giving you no way to defend yourself. Now while that may seem to be a good thing and be more scary, allowing you to have a fighting chance prevents the game from becoming boring and monotonous.

If you've been waiting for a proper Alien game this is as close as you're gonna get, great campaign length (took me 21 hours on Hard) and wonderful atmosphere make for one of the best survival horror games.