I would redesign the ramp and the towers. They just don't fit in really. (looks more like some Disneyland castle)
Also, try to use more different textures for walls and floor. The wooden room in screen 3 is all the same.
If the outside of a building is bricks, why would the inside be wood?
Other than the textures and towers it could be a good map. Keep working on it. (It might be tempting to start a new one, but don't. I made that mistake too often and I find too much unfinished maps on my HD. Most of them where crap anyway =p)