I have mixed feelings about GameSpot reviews and reviews in general. I used to have a lot of respect for GameSpot but they've done several terrible reviews over the years and often come across as extremely arrogant. I tend to read reviews from several sites, hope to play a demo, then make a reasonably educated purchase.
I'm about 6 hours into the Doom3 single player campaign. The game is defnitely a techincal achievement with insane graphics and remarkably smooth gameplay considering the graphics (from the perspective of someone playing it on an AMD 3000+, 1g RAM, ATI Radeon Pro 9800).
I've read that the SP campaign is only about 20 hours long, which is pretty standard these days IF the campaign is of high quality. I think so far the campaign is of high quality but I seriously doubt I'd want to play through it a second time - at least not for a long time. The campaign is highly immersive and scary as hell (I've had chills and/or a racing heart many times so far) but it's also extremely linear, has some (well done) scripted scenes, is pretty much repetitive corridor/room/indoor fighting, and has some annoyances (well covered in the GameSpot review) like the flashlight and trivial plot elements via the PDA). Unless you're a hardcore Doom person I think it'd be somewhat tedious to play through Doom3 more than once - compared to other somewhat similar titles like Halflife, FarCry, or Call of Duty.
I kind of don't like how Doom3 maintains suspense by what I consider cheesy mechanisms (like darkness and shadow), stealth undead, critters continually materializing behind you, and the fact that somehow this base is littered with a ridiculous amount of secret compartments perfectly sized to contain minions of hell. Oh gee, I'm in a room. Oh gee...the lights just suddenly went out and two huge secret compartments opened up unleashing demons from hell. I wonder who designed THIS starbase. Normally you'd think an expensive Mars base would be efficiently designed to conserve materials and space - which wouldn't likely involve lots of extra secret compartments just in case all hell breaks loose and zombies and demons need somewhere to chill while waiting for the hero to pass by. Seriously - some of these zombies were recently base personnel and now they're "hiding" in secret compartments?
Anyways....
I kind of prefer the terror that FarCry inspires where the damage model is more realistic, the enemies use the same weapons as you, and the enemies scare you in broad daylight because they have decent AI and if you make the slightest mistake you're in serious trouble - compared to Doom3 where you can take surreal amounts of damage and terror is maintained through a lot of very fantastic means.
Another thing that bothers me about Doom3 is the jacked up price tag. Yeah, it's only $5 more than your average premium game and yeah, it has insane graphics - but is it really worthy of the extra money, especially if this starts a bad trend in everyone jacking up game prices?
Anyways, due to what I see as limited replayablity, the jacked up price, and the elements of ridiculousness that detract from anotherwise solid gameplay experience I'd have a hard time rating Doom3 really high. Doom3 is technically brilliant and graphically amazing and is highly immersive but I think if you judge the entire package you have to consider its negative elements too.
Ultimately no matter how I'd rate Doom3 I think it's worth playing if you can afford it and have a machine that will run it. Even if you can't replay it that much and even if it does have some cheese factors it's definitely worth playing for the graphics, for the carnage and gore, and for the simple fact that this game will immerse you and scare the crap out of you.
Paul