Well I've fixed most of the wall texturing problems. Some of the doors are upside down, not too sure what's going on there. I'm still only rendering the right side of the linedefs though as I'm unsure what to do with the left. Adding two walls at the same spot is just asking for some z fighting.
Anyway things sure look a lot better than last night:
Doom 1, map 1
Doom 2, map 6 "The Crusher"