http://www.gamespot.com/xbox/action/doom3/preview_6115912.html?part=rss&tag=gs_previews&subj=6115912
"By and large, this console take on Doom 3 definitely appears to stand up to the PC original, though obviously in a somewhat lower resolution than the PC version is capable of"
"One example we were given is that the game's opening sequence--a long walk through a calm outer space base--has been shorted down to about two minutes or so, which should get players into the gunning action much quicker."
"Perhaps the most interesting thing about Doom 3 is that it will contain a two-player cooperative mode, which wasn't present in the PC original. This mode will be playable over system link or Xbox Live, and should allow for some new tactics, like having one player shine the light on an enemy while the other blows it away."