I got a free p/review copy today. It shows promise, but it's not great yet.
My eyes are sensitive to bright light over broad areas, so the art style in its default state gets annoying. However, I turned off SSAO in a configuration file to make some areas appear less murky, and I lowered the brightness on my monitor, and it was fine. The developers said that they had originally colored the environments, but playtesters responded in a certain way to the game with that specific colorless filter. It's likely that the assets are still designed with color in mind, so I think it would look much better if the devs recreated or edited them with high contrast and monochrome in mind. I also support any initiative to tone the blinding white down to maybe a light gray, with white reserved for intensity like the sun. With the brightness down and AO disabled, I had no problem navigating or finding enemies or items.
What's good is that you take few hits before going down, and the ranged enemies seem capable of leading you. However, they deserve more complex AI. Ranged enemies stand still and fire at you, and melee enemies run at you, and that's really it. At least some of the devs were technical guys at Monolith, which was an AI powerhouse. Condemned was their worst that I've played, and even that had enemies who would try to take cover, ambush you, run away when wounded and so on.
What I'd suggest is an AI system that tries to make use of the landscape and the visual style. Ranged guys probably shouldn't need to move around much, since people tended to shoot things while standing still back then, but it would be nice to see them move to higher ground or some kind of natural cover before shooting (the area is full of hills, after all). Right now, all they do is roam around and then stop everything once they see you. And for melee guys, I'd like to see them attack with a sense of self preservation. Since shaded areas are very dark in the game, melee enemies could run for cover of darkness under trees and such once they spot you, provided that shade would also darken their auras. Maybe they could just stick to shaded areas naturally. If you get near or if you turn your back, then they'd decide to attack. This is really just me fantasizing, and I don't know how high the combat is on the list of the developers' priorities, but their pedigree gives me hope that AI is something they can focus on.
Exploration is pretty interesting. The quests/notes screen also contains a tab about people who lived in this place, and as it seems, you get to find clues that add to their biographies. Things like tombstones describing them and stuff. The story looks like it will be pretty gritty and interesting, too. All the mission critical clues have bright red auras around them, though. I would have preferred that they be tinted or colored red.