WGRealms 2 is an action packed fantasy style total conversion of DukeNukem 3D. You don't need Duke 3D for this; just download and play!
A good total conversion for Duke Nukem 3D with a fair amount of reworked weapons, maps, enemies, etc. (by the way, it uses materials from Doom 2, Heretic and other 2,5D-games, but it's alright because they look good enough when combined together here). The main drawback which may even stop some players completely is the puzzle system which is unintuitional and it's sometimes difficult to figure out what you have to do to advance in a game.