The dirt feels too much like ‘just dots’ to me. I'd make it more subtle (not totally black), draining downwards coming from the roof and corners, and ideally using some fracture patterns.
There are procedural dirt generation tools like this: http://www.enrichpro.com/en/richdirt/index.html
Maybe that's some useful inspiration about where dirt usually appears (basically the same spots where you would get dark AO). Maybe there are even similar tools for UE.

But if you ask for feedback on visuals, my biggest concern is the rigging of arm pits for the main character. This is what i mean:

Real world arm pits:

Game arm pits:

The skinning bulges the shoulder plates inwards, creating a kind of hole and a narrow and thin back. Looks especially bad for male characters. I often notice this in games.
You should be able to improve this by reducing the weights of the arm affecting the back.

Btw, i often wonder why people make horror games in 3rd person. 1st person would be just more immersive.
The player becomes afraid of taking harm ‘himself’, which is something else than seeing some poor avatar suffering.
I think that's the main reason why games like Resident Evil did not scare me at all, while Penumbra then was really terrifying.
So did you consider 1st person? And what made you settle at 3rd person still?