There are only two source ports available for the Shadow Warrior: JFShadowWarrior and ProAsm's SWP.exe. I recommend you to use ProAsm's SWP.exe, which is, in fact, an enhanced version of JFShadowWarrior, with several fixes and enhancements added.
Please see the game's article at wikipedia for more game-related info:http://en.wikipedia.org/wiki/Shadow_warrior