I just beat the game, and counting from my own clock it took me 3 hours 45 minutes.
I'll post my review below which is an altered template from my usual custom story reviews. I'll keep it SPOILER FREE with spoiler-related talk added after the review in spoiler tags..
Mapping/Setting/Graphics:
Triple A quality through, and through. There are tons of greatly detailed environments, and good variety to keep things fresh. you'll go from standard interior office spaces to showers to sewers, and even to some other stuff.
There are a few places where you can very noticeably see re-used assets as well as animations which although isn't such a big deal can seem a bit jarring.
Scares/Atmosphere:
Let me first spell out the summary of this section in a nutshell: Outlast is 80% thriller, and 20% horror.
There are definitely traces of horror in Outlast but rather than to call the feeling fear I would more appropriately dub it exhilarating. You can really feel tension as you are being chased either when you are spotted, or a scripted one.
In creativity it doesn't help that the enemy appearances become insanely predictable as soon as you catch wind of how it works. Need to do multiple things to make something work? Enemy incoming.
Story:
The story...works in quite a strange way. The story seems to by the middle branch out into numerous plot aspects which seem to each resolve on their own, but sometimes I can't help but feel certain things could've been handled better. All these plot aspects eventually make the story very confusing, and extremely hard to properly follow.
Despite this I still found the overall nature of the plot to be somewhat interesting, and charming(?) enough to keep me invested in going on.
Gameplay:
I personally thought the gameplay flowed nicely in terms of running around doing what you had to do (Although the extremely predictable enemies I mentioned earlier annoyed me)
I thought the use of the camera was handled very well. I do not see a reason for you NOT to use the camera at all as when it's not in night vision mode it doesn't take batteries, and gives you notes. Battery placement was ideal, and forced you to be strategic about how you used them to not run out.
I managed them in my run very well with my lowest battery count being 3 when at other times it usually hovers around 7.
Technical Issues:
No real bugs in the game at all, but....
...*Goes into TotalBiscut mode* are you telling me that I can only customize three settings textures, effects, and shadows? Thaaaattt's not really ideal.
Verdict: A thrilling game which could've handled its story just a bit better. 7.3/10
Now for some spoiler-talk!
Spoiler below!
So what exactly was up with the entire Father Martin thing? Was he just running around spreading his beliefs when he saw you, a person with a cam come by, and decided for you to be the one to spread it to the outside world? If so why did he even let his minions (Namely the two naked folk) run loose on you in the first place at all? Killing you is not going to solve any of his problems whatsoever since you can't bring the footage to the world.
Also another thing I have an issue with is the macho man (Forgot his name but he did have one) What was his deal? Somewhere in the middle your character speculates he's actually trying to prevent something, but it's never played out, and I can't really see him as anything more than a common super goon.
Also how in the world does he get around so quickly?