If you want to see some amazing stuff, watch some top-notch Doom demos sometime. I particularly enjoy the ‘movies’ (full runs of the game on Ultraviolence or Nightmare!) and the Tyson runs (kill all monsters using only fists, berserk fists, chainsaw, and pistol).
Tyson almost matches the way I play. Not that I restrict myself so severely, but doing well at Tyson often means triggering lots of monster infighting, and I love to do that in order to save ammunition, and just because it’s fun.
Watching some of thse has also got me trying to play through the game without reloading a save or dying. So far I can get through to around level 10 of Doom 2 (I don’t have Ultimate Doom actually… back in the day I only had Doom 2, so that’s all I have now yet).
Of course, these demos would be more fun to watch in PrBoom if I’d get around to fixing the two crash bugs present in the game on PPC Mac OS X.