Just played through it, and I second the other posts, very good work
Just 3 real problems I noticed. One, the water has purple checkers. Two, in the Blu flag room there's a gray box in the corner that seems really out of place. And also in the Blu flag room, the cabinet isn't against the wall, there's a huge gap. All points considered though, very nicely done. Are the hills in the backround part of the skybox, or did you add those manually?