Extremely atmospheric but let down by weird quest and gameplay choices; and annoying bugs.
It seems like the developers have put all emphasis on creating a game where survival and gritty realism feels like a big issue. You have to eat, your weapons degrade, ammo is usually an issue, you have to use bandages, low accuracy weapons, you can die fairly quickly if you aren't careful etc. Now I really enjoyed all these things, it made me think about what I was doing, I felt like I didn't really want to enter a firefight with 100s of enemies but this is the really weird thing. Almost all of the main missions involve you sneaking into a base filled with 100s of enemies. It just doesn't add up. They put all this emphasis on realism and surival but then make you go on suicide missions. I probably wouldn't complain if it was actually a feasible option to sneak through these missions but it literally never is. The weapons are incredibly inaccurate. At first I actually liked this, it added to the realism of a post-apocalyptic place, and added an extra dimension of luck and craziness to the firefights, but when you get slung into a firefight with 100s of enemies, particularly with the weapons from the beginning of the game which are really inaccurate it just seems ridiculous. I've actually had firefights which have lasted hours, because I've run out of ammo with good weapons and had to resort to pistols which have no range at all. This brings me onto my next point: bugs. A lot of things I'm not sure if are delibarate or just bugs, which is an incredible immersion breaker. Sneaking being one of these things. If you try and sneak your way through a main quest, which you won't be able to do because of the placement of enemies anyway, you may encounter situations where you actually can't continue without alerting someone. I've been in corridors leading to areas I need to go, where I can't sneak up and stab the guy in the back (in full sneak mode, with no one else there to see), and I can't sneak past. Either sneaking is impossibly hard, or there is a weird bug here.
The worst bugs I've encountered have been to do with respawning enemies. I've completed 'defend an area' missions, been congratulated by someone, only to have it get attacked again a second later, until all my defender buddies are dead. It just seems like either a bug or a really weird gameplay choice. Other times I will be infiltrating a place with an endless supply of enemies, coming from places I just cleared out. It is just weird and immersion breaking.
The whole game just feels really strange, I'm sure by now most of the bugs have been stamped out, but the core quest choices can't be. It feels like they have come up with original gameplay mechanics and then giving you levels that don't suit it at all. Imagine they came up with the gameplay mechanics for Splinter Cell, based completely around sneaking and instead of making levels that would suit sneaking they put you in levels like those out Battlefield 2. It just doesn't really work.