saying you didn't have the whole budget is not an excuse for sloppiness, like those stairs at base 2 for instance they are horrid, I would suggest using a wall or something to line them up so they are all at the same angle.
Mmhm. It is a fantastic concept, but a lot of the interlocking is just piggish, no offense. If you touch it up and add more to the middle of the map, this could be golden.