So this is where I keep my UT99 mods, RipperArena and MessyKitty, now. Thanks must go to u/1337GameDev on Reddit for reminding me that GitHub exists.
For RipperArena and MessyKitty, put all files from the archives into your Unreal Tournament installation's System directory. For CTF-IrregularSpace, put the archived file(s) into your Unreal Tournament installation's Maps directory.
Back when UT99 was new, I got into modding via UnrealScript as was built into UT99. Sadly, I lost my dev box due to an unplanned emergency move in the early 00s. I recently rediscovered UT99 and, of course, retaught myself some UScript and immediately fixed one omission from the original game; there was FlakArena, but no RipperArena!? I also made a gimpier version of my gore-boosting mod, although it's a work-in-progress and is nowhere near generating the decal spam that its predecessor did.
Yeah, I know you want it. I'm still trying to figure out GitHub, but as soon as I have, I'll post the source code. As an appetite-whetter, I'd suggest looking at MessyKitty's use of the victim's Trace() function to spam blood decals. Also, check the way I did the spread function -- it's using the surface normal of the hit. :D
Meantime, you can open the MessyKitty.u file in a text editor and see the source.