Zenith is a large single player campaign for Unreal Tournament '99. which takes place years after Prisoner 849 escapes from Na'Pali, and long after the establishment of the Tournament.
As an anniversary token I added a few things that were supposed to go into 1.1.1 but were never finished. Nothing big, just a few changes here and there. Be sure to install it in the root UT99 directory (which you will have to set manually if you are using a Steam-based UT99)