Nice work! Pathfinding and AI is one of those things I've had problems wrapping my head around. I like the modular design, it's a nice "shortcut" of creating a huge amount of possible designs. The game itself is functions fine, not sure how to get rid of the box for building things once it pops up if I don't want to build anything right then and there.
For a game jam I don't think you need quite so many different levels as many people will probably only play the first few, so that would free up time to polish other things than making levels (though I am not saying it's bad to have many levels).