Its always nice when people like what your have done.
This mod is getting some good momentum on steam workshop and people seem to like it for the most part.
The source files for The Tomb of Zarthos have been released on Nexus.
http://grimrock.nexusmods.com/mods/60
Feel free to use any and all assets found in there in your own mods.
Feel free to modify or change anything that you find in there also to fit your own creations.
Keep in mind that the code can be messy on parts

There are some console errors when running it from within the editor, (just warnings) but everything works in the end.
I will be putting all my effort into my new unnamed mod that will take place outside (think Ishar from the Amiga), screen shots from early alpha can be seen in this thread. (maybe not "all" my effort

Best Regards.
Skuggasveinn.