Well, I got it yesterday and have played through the first few levels. I just don't see how people are so disappointed in this game. I already see people selling it on various forums--I'm not sure if that's because they've figured out how to copy it and are selling their store-bought copy or if they are just that let down with it. If you like FPS's how could you not like this game? Yes it's dark but I love the atmosphere. It's a little annoying to have to switch between the flashlight and the gun, but that creates more tension. I'm not totally blown away by the game as in "OMGOMGDOOM3FORLIFEEVERYTHINGELSESUXORZ" but I'm not disappointed that I spent the money on it. The graphics are amazing and it plays nicely on my 2-year old rig (P4 2.53/1GB/9700 Pro) which made me very happy. I'm running at 1280x1024...I don't have the horsepower to push 1600x1200 smoothly yet but that should change after I move to an Athlon64+6800GT and honestly the game looks damn fine at 1280x1024. I enabled 2x and 4x AA last night and could not tell that much difference in the graphics at all, but there was a big hit in performance so I disabled it. Not a big deal.
Another thing I'm not really thrilled with is that the AI could be better and there could be more enemies to fight at once sometimes--the most I've run into is 3 or 4 except for the one part with the spider monsters at the end of one of the first few levels. But it's not enough to make me quit playing and sell the game. I think once mods start coming out for this game it will be crazy because there are a LOT of cool things that people could do with this engine! I wonder if id will release an expansion pack?