Thanks man! This is great feedback. Yeah, you can currently drive over the UI. I might try to fix it with a combination of decreasing the UI size with a dedicated building menu and the player not being able to move this far to the borders of the screen. But overall, I want to rework the camera a bit overall. As you mentioned, it's currently a bit awkward.
When it comes to the balancing of the enemies, I think adding a radar that shows the size of enemies would also go a long way toward doing so.
Thanks for playing my game! I really appreciate you.