Brutal Doom [official site] isn't your grandfather's Doom II, is the sort of thing I'd say if I wrote for a games magazine in the '90s. Its reworked weapons, enemies, and combat do change Doom an awful lot, making it an ultraviolent new game with a friendly old look. Now Brutal Doom has its very own story campaign, blasting through a Mars base, down to Earth and across Los Angeles, then into Hell. Skipping through a few maps, I larked about in toxic waste, lead an AI squad through demon-infested city streets, fought the biggest dang Cyberdemon I've ever seen, and generally had a gay old time.
The Hell on Earth Starter Pack's levels are designed for Brutal Doom's different play and bring a new continuous story, with levels starting where the last left off and adding a few voice-overs and all that. Yeah, it was pretty cool to blast through the streets of LA backed by marines and the occasional tank, and I'll return to see the whole thing once I've wrapped up work. The story's thirty levels long, introducing several new bosses and whatnot, then those other two are, in classic Doom tradition, bonus Nazi levels. Check out some of the flashy set pieces and battles in this trailer:
You can download the Starter Pack over here. It can run standalone without Doom at all, but will be a bit wonky and not look as nice. I'd really recommend copying the Doom2.wad file from your Doom 2 installation into Brutal Doom's directory to get the original and proper art.
Having been delayed a bit, the map pack finally arrived last week alongside a new year and a new version of Brutal Doom. V20b brings big performance improvements, a rebalancing, more death animations, and other stuff. If you've already got Brutal Doom and simply want the update, not the new maps, that's here.