Doom 3 clearly redesigns the map for the medium more because of it's skin rather than it's meat.
Doom3 isn't a proper sequel but a remaking per se, of the old-school shooter. There is absolutely no need to fill up on plot points but no matter how much criticism this game has endured, the plot is actually quite deep {(*spoiler*) this game actually tells the history of the human species as it was before even the prehistoric times; as a fiction}.
While the gameplay is as simple as ever it is extremely heavy and adrenaline fueled. This is no Half Life, no Halo, nothing revolutionary or evolutionary about the gameplay, but a thick and atmospheric corridor run.
The best thing about Doom 3 are it's visuals. Phenomenal is probably the best word to describe it. The best graphical technology ever created on the face of the earth fuels this extremely atmospheric game. You will see lights flickering as it should in the real world, detached lanterns hanging from the ceiling and oscillating thus creating a kind of pulsing lighting around a certain area. It's all just brilliant. The overwhelming atmosphere of the game does an outstanding job of contributing to the gameplay. Somehow it manages to give the game a certain challenge. But I will not mention how, otherwise it'll spoil all the fun.
Finally, the creatures. The folks at id were surely mistreated and tortured badly during their childhood. The sadistic look of each and every creature is enough to permeate fear within one's soul. The way they realistically yet menacingly move, react to your presence and come running at you is too horrific.
About the Xbox version: I really think putting co-op gameplay for the Xbox was actually ruining the total experience of playing alone, though it does refine the gameplay in a sort of way.
Gamespot did not rate this game fairly, they put more emphasis on gameplay than its artistic visions (which is of course what the game is all about). Even if the gameplay has some noticeable shortcomings it's still quite a fun experience. This game should be considered a piece of art, it is awesome to witness the level of evolution the gaming world has gone through.