Made it to wave 7 before the link cable got stuck. Was an enjoyable stressful simulation the entire time.
Modeling of the towers was great, awesome work with that :)
I would have liked to get some kind of preview of the upgrade mechanics you mention in your game description. Right now it seems very "fill the progress bar". What kind of design space have you given yourself for upgrades other than just more towers?
A very polished demo though :)