Freakishly Good.
Playing through the game has a kind of a retro feel to it, if you played through the original Doom than you know what I mean. ID did an excellent job in creating a very spooky atmosphere in the game. I must admit that I felt chills playing through the game, the ambiance, the sound, monsters appearing out of nowhere. If you played through ID software's previous title than you will feel right at home. Just like in Quake 2 you are required to get this access clearance to get through this and that door, which is a very linear type of gameplay, which I don't mind. One has to also be very thorough, where one has to look through every nut and cranny to get that extra ammo. I also liked the fact that the PDA's from various personnel contains various information about the operation of the base that you are currently inhabiting, there recordings, which contains often valuable information about the codes to open containers as well as their e-mails which was amusing to read through, as well as looking at the various video's about different functions of the base which was quite interesting. It makes you actually feel like that you are actually there. ID payed vary close attention to detail. One criticism could be the fact that there is not much diversity in the levels, you are pretty much stuck in the same complex, with the exception of when you go to hell, and the last level. Another criticism could be that you have to switch between the flashlight and your gun when shooting enemies in the dark, although, I think it makes the game more tense and scarier. I could remember countless times where I would fumble between my flash light and my guns after a monster appears out of no where.
In terms of the graphics, ID Software's legendary track record of producing top notch graphics engine shows through this game. Although, it is has been five years since the release of the game, the graphics still holds up. Back in 2004 it was without a doubt the best. The texture detail from the enemies, to the environment, to the martian surface through which you have to walk through for a brief period earlier in the game showcases what awesome graphics this game has. Making top notch 3D engines is ID's expertise.
Overall, it was a descent game with excellent graphics. Nothing too revolutionary in terms of game play, but the spooky atmosphere and ID's close attention to detail makes this a game that no first person shooter fan should miss, especially if you are a Doom fan.