For my high school's CS class final project, we made a street brawler using doom characters. All the doom art was captured via opening a game and using print screen, then hoping the sprite was in the right position.
In retrospect, our sprites had their own lofi charm but yea, I never thought to just open up the WAD files.
That brings back memories of playing around with WAD files, pulling out graphics and palettes, reading level data and drawing it with LineTo() and MoveTo() calls, and running into all the limits of a 16-bit C compiler (Turbo C)...