I extracted with the zip files name, so it was:
g:\Spill\Galaxy\SystemShock2\SystemShock2FMs\FMs\RttUNNv1.01_sky+spawn-patched

as this it worked:
g:\Spill\Galaxy\SystemShock2\SystemShock2FMs\FMs\RttUNN

Great to play SS2 again, been some years since the last playthrough of the game and FM's.
The closest I have gotten to a game like this since ss2 is the latest Prey.
Still hoping for a new game in the veins of SS2!

Nice, having some fun with RttUNN now, but man, I find it pretty hard! Alt-S is my friend

It's a pretty impressive accomplishment for pre-NewDark ShockEd, but it's definitely rough in spots... or patches... or wide swathes. It's a shame Blaydes99 isn't still active in the community. It would be great to see what he could do with NewDark and all the knowledge we now have about how to do things.