I am planning on adding a few navigation options. Right now, once the game starts all you can do is click ESC to exit the game and that only works when the battle starts. So, I want to add the ability to go back to the title screen or upgrade screen. Was thinking of letting players reset their upgrades and reconfigure for every battle.
The UI being clipped off I should be able to fix fairly easy. The problem is I cheated and its not an actual UI layer which would be anchored by the edge of the screen.
Also, you had mentioned town HP increasing as the town is constructed. This already happens, I just didn't come up with a way of communicating it to the player. Ever round town HP increases by 5. I am thinking of replacing the town HP meter with orbs, one for each hit it can take. It would also match the player meters for a more consistent appearance.
One of the problems I had with accuracy and it took me a while to realize, is his arms are to his side. So when aiming, you focus not on the center of his body but where his arm is.