Doom 3 serves as an excellent technology demo but unfortunately exhibits some rather aniquated gameplay mechanics
The story of Doom 3 is a retelling of the original. The gates of hell have been opened and Hellspawn are killing everyone insight. No real context is given as to the how and why of things, you're just expected to accept it and kill Hellspawn accrodingly. It wouldn't be a bad concept if the game wasn't so story driven. Doom 3 has significant chunks of the story told through PDA messages that you find lying around the facility. However, in focusing so much on the story a number of criticisms can be raised about it that would otherwise be overlooked. The biggest is that the story isn't particularly well done at all. There is no expostion, no explanation as to the how and why of things and hardly any resolution. Again if the game focussed on the core shooting as opposed to the story this would not be a reasonable criticism but given the Doom 3's choice of going heavy on the story then the this criticism is fair game.
Gameplay wise, Doom is definately fun...for about 5 minutes. After that point you start to figure out the patterns of the game. You'll walk into a room and if you're not attacked by a zombie you can be guranteed that there will be an Imp and even their spawn points are predictable. You can almost gurantee that one Imp is going to be infront of you and the other will be behind you. After you figure that out you'll also figure out that they only have one attack that is extremely easy to avoid and considering that throughout most of the game you'll be battling nothing but these Imps its hardly any fun as there really is no challenge.
It would be criminal though to not acknowledge the uncanny level of atmosphere created by the game. The game will make you jump out of your seat on more than one occasion. There are moments that will have you fearing an advance. Sometimes you lose control of your character and will be surrounded by creepy voices. Id has done a superb job of creating a terrifying atmosphere. However, as good as it all is, it becomes old real fast. The same tricks keep appearing over and over again and thusly takes away from the intended effect. That said though, the atmosphere created in Doom 3 is still among the best in the genre.
Doom also features some really old level designs. The flow of the game seems to be that you enter a room, the door to exit this room is locked, you'll kill a few enemies, find a key and unlock the door only to do the same thing in the next room. While this wouldn't be so bad if it happened a few times, every level in Doom follows this principle and considering that Doom has a fairly lengthy campaign it makes for a boring game. Needless to say, finishing the game will seem more like a chore and less like an exhilerating thrill ride like Fear or Half Life 2.
However, Doom 3 isn't all bad. In the audio department Doom 3 takes an interesting decision and decides not to have any real soundtrack worth writing about, save for a pretty good metal track during the title and end sequence. Other than that Doom 3 relies on ambient sounds and some cool padwork to paint a scene of tension and certainly immerses you in the world. The mix sounds great on a stereo setup, however, the mix really comes alive with a 5.1 setup. You'll hear the shrieks of the various demons and they're as loud as a banshee. Needless to say they look and sound terrifying. However, for some reason your firearms just don't pack a punch sound wise. They seem kind of flat but with a stellar audio performance on everything else it is hard to really notice this. Doom 3 definately plays better on a system with surround sound as sound is such a key element of the game so users with surround sound configurations will get an extra bonus from the game in that regard.
Doom 3, while some character models don't make alot of sense (IE: Scientists), has some of the best character and boss models seen to date. The Imps are detailed to perfection and almost every enemy that you'll come across will look terrifying. At times it is hard to grasp that these extremely high polygon character models are all being rendered in real time. However, Doom 3 also has some stellar weapon models along with an excellent array of weapons. You'll find the mandatory FPS guns such as the Pistol, SMG, Shotgun but you'll also have a Plasma Rifle, Grenades, Mini-gun and of course how could anyone forget the "Bio-Force" Gun (BFG). Doom 3 really delivers on making these firearms look and feel good and you'll definately be satisfied while using them.
There are some weapons that don't work very well. The explosive weapons especially come to mind. Doom 3 is a largely claustrophobic affair and you'll rarely have an occasion to use them and if you are forced to use them, you'll likely hurt yourself more than your enemies. The second questionable weapon is the chainsaw. Sure its old school and will please fans but its implementation is abysmal. The weapon could be a solid addition to a fine roster of weapons but it appears that no effort at all went into refining it. What you're left with is a crude empty shell of a weapon that does nothing more but add another icon to your inventory.
In terms of Efficiency Doom is demanding to say the least but it will run well on older systems. The lowest card that could run it well would probably be either a 9600 or one from the FX line of cards. Anything lower and an upgrade would probably be reccomended. However, Doom 3 still looks very impressive on lower settings and though you might not get the absolute most crisp textures you'll still be able to see the incredibly well detailed world of Doom 3. However, to get the most out of Doom 3 you'll definately want a high end video card, an x850xt or a 6800 GT should get the job done with superb results.
In terms of replayability value with Doom 3, there isn't a whole lot to be had. Yes there is a harder difficulty level and nightmare mode. However, the game isn't that hard to begin with so the harder difficulties won't offer much in the way of a legitimate challenge. Furthermore, the Nightmare mode itself will do more to irritate gamers rather than provide a rewarding experience. In this mode, your health constantly declines regardless of your activities. It doesn't sound good on paper and it doesn't execute well either. So that leaves the multi player. Some games can be saved simply on the strength of their multi player, unfortunately this is no the case for Doom 3. The game frequently suffers from latency issues and there is a 4 player cap. The whole mode itself seems slapped on and lacks any refinement. In all, once you've completed the story mode, you're done with Doom 3. With that said, its really hard to say that Doom 3 is worth the price of admission.
To wrap things up, Doom 3 definately is impressive from a technology standpoint and serves as an excellent example of the power available these days for graphics. However, poor level design and gameplay really ruin what could have been another great First Person Shooter. With a lackluster campaign and a multiplayer mode that seems almost neglegted its hard to reccomend Doom 3 to PC gamers when there are other excellent First Person Shooters that use the power of todays systems along with new gameplay mechanics and level designs. If you're a hardcore Doom fan then buy Doom 3 but if you're just general First Person Shooter fan, save your money and look elsewhere because you'll likely be dissappointed with Doom 3.