First person shooting...just like mom used to make..uh, I mean ID software.
Gameplay
Just because a game is not complex, doesn't mean it isn't great. There was nothing more satisfying than walking into a room and having dozens of highly creative monsters running around just to get blown to bits with highly satisfying weapons. They say a shooter is only as good as its guns, and I'd have to say Doom II's double-barrel shotgun is perhaps one of the most satisfying guns ever created. Even to this day, I smile when I blow away ten zombies in one shot. Simple, classic fun that NEVER gets old.
Graphics
They may be completely outdated now, but I remember as a young kid seeing Doom on my computer for the first time and being utterly amazed. The walls, the demons, the guns, everything! They are forever etched in my mind as classics.
Sound
I may be one of the few, but I actually listen to Doom II's soundtrack on my computer. That midi music may be simple, but damn it's catchy! Not to mention the sounds of the demons, but I think everyone can agree that those are timeless in their execution.
Value
This is a game that I play through once or twice a year, just to relive the excitement. When you count the countless mods, technically, it could never end.
The Skinny
I cannot possibly express the love I have for this game. It is my favorite computer game of all time and anyone who hasn't already played it should break out their chainsaws and plasma rifles and start owning some spiderminds!