Ragnarok 2 is a mod for shareware Wolfenstein, made by Gary S. Tong. It was released on January 9, 2010 and followed Ragnarok which had been released in 2002.
10 new levels are featured, and some textures and doors have been changed. The original Wolfenstein feel remains, however, and as with the original Ragnarok, many levels are large in size.
It is playable in SDL, not featuring any source code changes.
Download Ragnarok 2 at The Wolfenstein 3D Dome