Just finished it. About 15ish hours.
What an amazing experience. Definitely the most memorable from last year. It ranked highly on my list, but if I had finished it earlier, it may have even taken number 1 from Dark Souls II.
The only thing I didn't like were the facehugger enemies. I felt like they were kind of cheap being arguably the most deadly enemies in the game. I also think the EMP grenades should have worked on the industrial Seegson androids. I never got a chance to use them much. I was a chronic saver, often going out of my way to run back and save after making a bit of progress when it made sense, so I never lost more than a few minutes if I got killed. The save system definitely added a lot of tension to the game, so I think it was the right decision.
Anyway, I had a blast. Not many other games are this engrossing. I'm definitely going to check out survivor mode and maybe some of the story DLC soon.