Thanks - it really means a lot to hear this, especially when I've only done 3 of these jams so far. I am trying hard to learn to focus my time on the right things. =)
Honestly, I thought this idea wasn't going to work at all, and I'd have to add a bunch of enemies to make it challenging, but then when I implemented it I found that even the simple levels got so chaotic that it didn't really need them.