It's not bad, it just could have been 100 times better. Of course that would've required massive levels and whatnot. I was impressed with how good it was, honestly. I look forward to their future titles.
Also, Metro 2033 is a bestselling novel in Russia, further proving that country is pretty damn cool.
After playing it a bit I'd have to say it's more of a blend between Doom 3 and the old Thief series than Fallout. My only gripes are that things with the sneak system that could be a little more fine-tuned.