Thank you Zen00! Really appreciate the feedback. The bats flying up is a known issue that I just decided not to fix. You're pretty spot on about doing it outside their target area. What's happening there is they are switching to their follow state when you shoot them, but because you've already "left" their follow area, they switch to their unfollow state and return to the sky. Since this is happening all at once it just looks like they're floating up when you shoot them.
I plan to do an update which changes this, so that tactic should become obsolete in the next version. ;)
Thanks again and you're already on my list of ones to play! :D