Highly evolved engine based on id Software technology, available under dual license (GPL, proprietary licensing for commercial use available).
Alpha release = painkeep cube, morphic cube, crates, runes, regman quad-barrel dwarfcutter, quantum tunnel apparatus, super gravity well, chaos teleport sphere, power points, new maps, new and random monsters, frikbot, pkbot, pkplus support, more. Alpha code may fail - see disclaimer.txt, readme.txt, archon.txt.
You can find the latest quake-c bug fix here (progs.dat): Cataboligne.org
Copy (or download it) into the quake/archon directory (post install of course.) It will replace the one there.
That location will be updated frequently during this weeks bug hunt.
I will post the fix list in the feature forum: Moddb.com