Great in the beginning, gets old quickly
Gameplay in Doom 3 is pretty simple but fun. You walk around, shoot monsters. That's pretty much it. You really never really run out of ammo so, unless you have a really bad aim, you really don't have to strategize much about what weapon to use when. Level design is pretty simple too... there's almost no way of getting lost, that is good given that the levels are extremely similar to each other. It also gets boring to walk around after a while because monster are always the same (there are maybe 7-10 types overall), levels look the same and gameplay... it's the same. The are some very light (and forgettable) puzzle elements, besides the traditional "find the keycard for the door". Boss battles are OK, they don't require any particular strategy with maybe the exception of a couple.
Graphics
Nothing to say here, it's gorgeous. The X-Box really has a next gen look here (less shiny, more blurry, but still...). Everything moves really smoothly, lighting effect are very well implemented giving the game a really creepy feel. Physics are also there, but are very limited and don't really impact gameplay. On the bad side, some textures are really blurred and in general the game really lacks variety. There are basically 3 type of backgrond (space station corridor, hell and caves) and you will see them for the 12 or so hours it will take you to finish the game
Sound
It's appropriate in that is very minimalistic and dark. There's virtually no music, all you hear is space station noises (bleeps and stuff like that), creepy voices announcing you're gonna die and monsters' rattles. Sound really contributes to the atmosphere but gets repetitive after a while. There also are some dialogues, pretty well implemented
Value
I bought the collector's edition and honestly don't think it was worth the money. Yes, there are Doom and Doom 2, but I haven't played them anyway. The game is a good deal for maybe 20 bucks but wouldn't spend more than that
Tilt
Once again, the game strikes you in the beginning but then gets old kind of quickly. In the end I was praying for the game to end, because I had had enough of running around and shoot at the same monsters in the same corridors. All in all if you are looking for a game to showcase what your X-Box can achieve graphically, this is definitely an excellent choice. If you like the Doom run'n'gun concept (understanding that there isn't much beyond it) the game does the job. If you are not a big fan of FPSs, this game will definitely not change your mind