DOOM is still one of the best fps games out there and today there's still alot of games that can't top it.
The story involves a project on mars that goes wrong and it opens a portal to hell and the rest of the game is just killer entertainment (literally).
You start out with only a handgun and you fists but as the game progresses you get an awesome arsenal of weapons like the rocket launcher, chain gun and of course the BFG 9000.
The game also have a nice variation of enemies like the spectre witch is invisible, the imp that shoots fireballs and the hellknight that also shoots fireballs but it takes more damage and it can absorb more firepower.
There are four Chapters in total and the environment turns more hellish every chapter until the end where you finally go in to hell and also try to get home.
This game is different from other fps games since you can't look up or down but as long as you have an enemy right in front of you or over you, you will still hit it.
It can be a little hard to navigate through the later levels because they're bigger and they can be a maze sometimes and you will end up running around in circles sometimes but the good thing is that you have a map on the Xbox live arcade version but this is the pc version so prepare for some backtracking.
The music in this game is a master piece, it has this rock kind of music and it's just perfect for this kind of situation and it is a new soundtrack for almost every stage witch is just awesome.
The sound effects is also gold, especially the weapon sounds.
If you're not a fan of shooting games this isn't for you since it is a tad bit repetitive since all you do is looking for key cards and killing demons and zombies while at it, but i still recommend this game for everyone who haven't played it yet and i promise that you will have tons of fun while playing it.