Question about distributing an addon
I am working on a mod of Wolf 3D. I want it to be stand-alone so I can put it on my website for everyone to play, but I wasn't sure how legal it would be. I'm going to make sure that all graphics, maps, music, sounds, etc. are changed, and if they can't, that they are in the free shareware version. It'll also have some source code modifications. With these changes, is it possible to legally distribute the game with the data files or will everyone that plays it have to own Wolf3D first?

If you change MOST of it (as in just about everything, though many mods left the weapons and some of the enemies intact) and have a new exe it should be fine.