Demon Hunter is possibly the first mod for the old Hovertank 3D. Although made at the end of 2006 it is quite less rotten and features an apocalyptic sci-fi/fantasy setting.
This is the full version of Demon Hunter. The Game requires the original Hovertank 3D "HOVER.EXE" and "DOCSHELL.EXE" files to run. Version 1.1 includes a patch to add the story to the game. First run the patch and then start the game (hover.exe or start.bat for more info). The game works in older Windows versions. Otherwise Dosbox is required to play.