Proasm shadow warrior port is based on jonof port (the same guy who worked on the duke3D port which Duke3DMegaton and eduke32 are based on).
Original files are required to play, just unzip Swp432.zip in SteamApps\common\Shadow Warrior Original\gameroot\ and run SWP.exe.
be careful there a bug with savegames sometimes.
To fix sounds set compatibility mode to "Windows Vista".
there also an HD textures pack with 3d models if you are interested, look over duke4net forums (http://forums.duke4.net/topic/3412-shadow-warrior-high-resolution-pack/
or there the direct link to the files if you don't want to mess with SVN tools : sw_hrp.Rev 17 2012-07-05 .7z (65.5 MB)
extract everything in SteamApps\common\Shadow Warrior Original\gameroot\ and run :
- HRP.bat (High-Resolution-Pack)
- LRP.bat (Low-Resolution-Pack, The LRP contains 75% scaled down versions of select assets from the HRP for use on slower PC's and laptops. It is completely dependent on the HRP)
But the game look way better to me without that texture pack, just use SWP and set texture filter to Linear