You should work on your proportions and textures.
Let me sum some things up:
-The door height seems alright, the wall starting above the door is about 1.5 times as big as the door itself, doesn't make sense.
-You use outside brick textures for an inside building
-You fill the halls with object, which doesn't really make it playable
-It seems as if there is only 1 route to walk
-The tile / scale of the brick isn't in proportion as well (too big).
-Desks are about neck height(desk should be just where the legs end)
-Make both doors for rooms be open, 1 is too hard to get into and causes frustrations.
Besides all that it looks pretty repetitive, work on your level design.
