Broken textures and such

The weird part is that reinstalling the game doesn’t seem to fix it. Even if I first remove all gmod related files and then delete the files through steam, reinstalling still doesn’t do anything.
What I notice is that the game download is a 2 gig download, when it should be a 3,8 gig download. What is this even?

edit: Heres a screenshot of what maps look like. http://i.gyazo.com/7713312dcc90c73b8431e014efb67d00.png

edit 2: Ugh, well sorry for possibly wasting your time. I fixed it! My problem was that I had inserted -dxlevel 81 into the launch options when trying to get a map to function.
Turns out removing it did not turn the dxlevel back to the default one. So I inserted -dxlevel 90 and it seems to be back to normal. Hope that helps!