Hey thanks for playing my game!

-I went back to test and the player does lose health. However sometimes  the bats attacks don't register properly. They still need some work as I've noticed they are a little buggy and sometimes lunge at nothing (Slime and Giant Slime should do damage though). It could possibly be because all of the enemies are pretty easy to dodge right now and you may have not got hit directly. I think this will be more apparent if I had stronger enemies or buff the current ones.
-The shield only heals the main base, not the towers. I plan on implementing a new pickup that will repair towers health by some amount in a future release.
-You are right about the wave not looping correctly. I edited the wave system to allow multiple enemy types in one wave as opposed to only one. However I did this in the last hours of the Jam and didn't realize this bug. Thanks for pointing it out. I will make this a focus on the next release.
-That is a great idea! I agree that the game is definitely missing some story/lore  and instructions on how to play. This became very apparent to me while testing other people's game during this jam and is something I will definitely try to incorporate once I flesh out some of the other core game mechanics.

Thanks again for your time and feedback!