I just picked this up today for $29.99 + tax canadian, surprisingly some places discontinued carrying it. Anyhow, here is my take on my hour or so with the game.
1) The Atmosphere: This game is better enjoyed in Russian (yes because i am russian) but also because the things people say while you are walking around make more sense in the native tongue they were created in, not translated to. I think this is a major reason some people get turned off but the lack of full understanding of what the characters are trying to convey to the player. There is also something special to being in a destroyed city/subway when you've actually been there and lived there yourself in real life (Moscow).
The game is not too dark, it used light and shadows very well. Doom 3 was dark, This game is just right, and yes you have to use the flashlight more often. After all, those characters are living underground in a subway!
2) The Visuals: So far i have spent more time tweaking the settings and playing with the config file rather than actually playing the game. That will change when i get it just right. Advanced DOF i believe must not have been coded correctly, there is just too much of a performance hit (about 50% as per HardOCP) with its on. Tessellation is kinda alright, but when you are moving and shooting you don't really pay attention to the fact the character's around you have rounded arms and what not. I also don't like how you cant have more control over the in game settings, but thats what the config is for more or less.
Its just not smart of the developers to make such a showcase when most people cant max out the game. So potential buyers read posts like this and reviews and think to themselves "My PC wount run this anyways so i might as well get COD or whatever that runs smooth maxed out on most machines) Thats how you loose sales.
3) Gameplay: so far after the little train cart scenario in the very beginning the game feels very satisfying. They create scenes similar in a way to COD games where you have certain action you have to perform kind of pre-planned, but they do it in a less obvious way. Its also not that hard to kill the mosters (yet), a few well aimed shots and they are down. The trading of the bullets, conservation of ammo, and little things like that are done to immerse you in the experience, not make it harder to play. They add to the realism of the whole experience.
Overall this game is kind of under the radar because of some of the things i just mentioned. Hopefully my next PC (in a year ??) will be able to max out the settings in this game, but so far im playing 16x10 + high + tessellation + advanced PhysX + DX11 (still tweaking) and enjoying the game...