
Don't use blend textures unless you are alpha blending or are using decals.

Make something like this fence detail so it doesn't look like there is a hole in the wall.

Heres an example of where alpha blending would be good as its strange how the road just ends.

Another alpha blending example

It's nice that you are adding this kind of detail but you should mix it up a little. They are in constant rows and would look a little better if you changed the positions randomly around a little bit.

This isn't an issue, just more of a suggestion. It would be cool if there was a way to get down from here. You can get trapped pretty easily and it would be nice to be able to jump off, but that's up to you.


These tank tracks are animated so its a little weird having this model stationary.

This roof just isn't that realistic IMO. I would recommend following blackjackjonnyy's roof making tutorial as it helps get more realistic looking roofs.
CoD Radiant : detail made easy : Detailed roof using patches
If you are going to do something like this I would recommend cutting the brush with the clipper tool in the middle.
Then just some other general concerns:
-buyable ending is too expensive
-buyable ending trigger is not noticeable enough
-pack a punch should be moved back into that back room more