When the first Doom appeared on Xbox live, I grabbed it and played it through from beginning to end, and thoroughly enjoyed it. Yes it was mainly the nostalgia, but it was a good port, very nicely adapted to the xbox controller, and even supported multi-player for old school fragging fun. 
Now Doom II is here. I was supposed to be playing Fallout 3. But I was having a thoroughly miserable time. The 'face on' conversations, with the 'choose your response' dialogue, seem stale in a post- Mass Effect world. I didn't really care about my character - or his dad! And I was tired of going a few feet in any direction before having a random encounter with something way tougher than me, and promptly getting killed. 
So I switched that off, and downloaded Doom II onto my Xbox. And I quickly cranked my way through 5 levels with a big smile on my face. id just knew how to make fun games, back in the day. Everything is as well ported as in the first game. I struggled to remember where any of the secrets were, and spent a lot of time bumping into random walls as a consequence.... but even that makes for a perverse kind of fun.  
(I'm not sure about that 'Take down the Cyberdemon by punching him' achievement though!)
I spent a fiver, and got a game which was instantly WAY more fun than the supposed 'triple A' game I was playing before which cost - what, eight times as much? 
Let's hope next year we get Quake 1!