Blood is an old game by Monolith Productions that is... really great. (I don't have other appropriate words here.)
ZBlood is, basically, a Blood remake on (G)ZDoom engine.
ZBlood+ is an unofficial fork of ZBlood. It has been holding "In Development" status for a bit really too much more time than it should have. It's high time at least something was shown to all interested parties (if any exist).
And now, ZBlood+ finally has something to show.
So, in ZBlood+ you're again playing as Caleb, kicking heads and empty buckets, boasting great firepower and firing the robed madmen from life (if they ever had any). The unsatisfactory "story" of ZBlood is still there unchanged, because writing stories is not my cup of tea, but having at least this story is better than just "hit the switch to end the level".
If you haven't played ZBlood, or just Blood, you can still enjoy it if you're interested in: infiltrating sinister cults, ludicrous gibs, red rains, horror movies, playing zombie head soccer, Doom not looking like Doom, more or less scary more or less atmosphere, and at the same time great fun blasting things.
Demo Version contains first nine levels of ZBlood, modified so that they run better with truer balance of ZBlood+. They're also a little bit changed here and there. I tested balance by playing it on the highest difficulty, and, trust me, it's possible. And really challenging.
Advanced Engine Needed: although it is totally compatible with ZDoom, it is recommended to play it with GZDoom. (It may even be too dark if you don't, as some maps rely on placed lights.)
Absolutely obviously, you'll need the latest SVN version of either one.
Download link: http://dl.dropbox.com/u/14235769/zb43demo.zip
Three files in it must all be loaded together. I don't think that order matters, but just in case, I use "stuffs, textic, levede" order.
Spoiler: To be or not to be (expected from the upcoming full version)
Spoiler: old post, for history and stuff%d-days only offering! Get the totally original remix of one of Blood's musical themes now! (the theme is cblood8 in case anyone is interested)