The floodgates of Hell have opened and you're stranded on a desolate planet armed with a pistol. As the lone survivor of an elite space marine organization, the fate of mankind is resting on your shoulders. You must stop the monstrous onslaught on Phobos before the destructive reign of terror reaches Earth. Needless to say, this is a snafu to the "nth" degree.

Ultimate Doom features hellish first-person action through 27 original levels (the first three episodes of Doom included) and an all-new nine-level episode. While the original levels have been left intact, Thy Flesh Consumed was created by veteran players. Levels generally incorporate dimly lit hallways, complex installation layouts and nightmarish cathedrals with demonic pentagrams and flickering lights.

While surviving the cruel landscapes is an absolute must, it won't be easy -- there are vile monsters roaming the hallways. You'll encounter former sergeants and humans, imps, pig-like demons (some of which are invisible), flaming skulls known as Lost Souls, and Cacodemons that resemble mutated balloons. When all is said and done and you think you've seen the end, you haven't...the Barons of Hell await. These mammoth creatures require truckloads of ammunition to drop and launch fireballs in your general direction.

There's an arsenal of weaponry located throughout each level. In addition to the default pistol and fists, you come across destructive shotguns, chainguns, rocket launchers, plasma rifles, and the end-all BFG 9000. Each weapon has corresponding ammunition pickups including shotgun shells and clips. There are also helpful items strewn about including radiation suits (for navigating toxic pools), security and combat armor, berserk packs, invulnerability, invisibility, and medikits and stimpacks that heal your character.

Ultimate Doom also features 640x480 resolutions and customizable WAD support; you can download and install files that alter textures, monsters, and weapons. Additionally, custom-made levels are available via download from the Internet or you can load them via floppy disk. When you'd rather blow your friends away in the virtual world, there's deathmatch support as well.