Some of the objects really need some work. Even at the time I thought, wow these are really old FPS models. More than just a texture update obviously, the gothic looking buildings really need a major update these days. They look okay from a distance, but up close they look awful.
Not a critique on your work Graphix, but a critique on the original objects. Back when they were made, they were probably fine, but these days they look beyond awful. TGC stretching their media library at the time me thinks. I'd be quite happy for you to remake the offending items from scratch
TGC, pay this man! Get others fixing old rubbish media!
Really, a lot of issues (slowdown included) would be fixed by updating all the old crummy media we have. Update it and you will have a smoother better product
SPECS: Ryzen 1700 CPU. Nvidia 970GTX. 16 Gig Memory. Win 10.