Why doesn't it let me run this map?

Hello, I decompiled a map and I modified it a bit. Whenever I try to run, hammer crashes and in the logs it says it can’t find material GLASS_CLOUD and a lot more materials…

How do I fix this?

Doesn’t look like you have the materials (textures, models, etc.) that the map uses.

Post the full compile log please.

Decompiling a map breaks all kinds of crap. Try to remake the map manually using the decompiled VMF as a guide/reference instead.

This is your problem. Decompiled maps aren’t for adding a sniper tower and recompiling, they’re purely for reference. If you want to make a custom version of a map, you need to rebuild the entire map with all new brushes.