Yeah, if I make a post jam version, I'd probably add a damped hit sound for whenever you hit a target that's too big and has more health, it's a little tricky because I wanted both finding smaller targets and shooting a big one multiple times to be valid strategies.
Curious, did you try shooting targets that were not the correct ball color? I imagined that situation being something players may not realize initially, and getting no feedback from hitting those targets possibly helps, but I'm not sure if I'm doing enough in gameplay to communicate that.