The scientists overrun Mars, unleash Hell, get nearly everyone killed and YOU are expected to clean it up... NOW.
The basic premise is one known to many a horror sci-fi movie: a science community has discovered and taken up residence in Mars City, a laboratory complex on the Red Planet itself and led by a rather creepy fellow who's right eye is missing it's pupil and tends to mutter to himself about his lack of budget. Concerned with the increased number of accidents and general fear gathering throughout the base, the Board sends an angry representative to sort things out - flanked by the never-smiling Sargeant (("You're the control, and I'm the damage")) Kelly. Also on board their shuttle is a nameless and soon-to-be rather confused marine... You. After wandering the premises for a bit ((blocked by several locked doors - they won't trouble you for long)) you are given your first assignment: locating Jonathan Ishii, a little lost scientist who apparently has "wandered off", as if it's not suspicious or anything.
When you finally locate the little guy, he's freaking out. There is a loud crash, the machines go crazy, Ishii develops a taste for your blood, and you are forced to resort to 9 millimeter reasoning with his head. From here everything goes quite literally to Hell as you battle zombies, imps, undead soldiers, and rocket launcher skeletons to find the answer to the ultimate question: WTF IS GOING ON IN HERE??
Doom 3's greatest charm is its perserverence in incorporating a story to its bloodbath. There are an abundance of PDA's to be located that are the ex-property of zombie employees ((the undead are bad with anything that has more than two buttons, so it's okay to take these with you)) and divulge tidbits about their personalities and jobs - some make you feel bad, some make you glad that the jerk got whacked. There are also computers with downloadable information concerning Delta Lab's iffy experiments and programs that offer a whole new dimension to the game. Of course these extras are completely optional so if you really want to just go in at a sprint with your plasma gun blazing that's okay too.
The difficulty settings allow for adjustable gameplay and the intensity amps a level just as you think you're getting accustomed to the game - usually by throwing in a new and interesting ((and sometimes downright wrong)) enemy to play with. Sometimes its action - swarms of fire-tossing imps in an open space - and sometimes its horror - entering a dark room and hearing BLEH followed by footsteps.... The two are juxtaposed well enough that they don't get irritating except for in a few places. They also toss in a few puzzles or maze-like areas to relieve the gore and you are occasionally expected to help out the scientists who survived that you locate along the way as a form of cheap and expendable labor (("go get this thing" "go get it yourself!")) in order to further your progress.
There are a few glitches and quirks in the game ((we managed to locate the Pit of Despair - completely inescapable without noclip)), but there are some really neat mods to be downloaded: Last Man Standing allows multi-player gameplay in story mode ((which is wonderful)), and the Flashlight mod. Doom 3 forces you to switch between flashlight and weapon with the F key as if any boneheaded marine were incapable of using both hands at the same time. The creator of the mod determined that any self-respecting military person would be bright enough to DUCT TAPE the light to the gun - voila! It's a good mod to use and makes the switching less irritating - thought for some reason it didn't take on the shotgun in my game. Oh well.
Doom 3 gets a good rating in my book - enough violence to be tension-relieving and enough horror to make me curse at the screen when I play in the dark and jump a couple of feet. Maybe by now the graphics are becoming obselete, and the glitches are noticeable in places, but this is a classic that shouldn't be missed by any open-minded gamer.