Thanks for the feedback, very glad you enjoyed it!
The final wave thing almost didn't make it in, so I'm glad it was worthwhile. 😉
I agree about the walk speed, it does start to get tedious to walk around building towers as the level expands, and I think it also ends up encouraging you to consolidate your towers around a single area, which is not quite what I'd like. (Although I think there are other choices at play there, too.)