I like the concept of clearly visible hit zones! It's very simple yet adds important variety to what would otherwise be repetitive shooting! I guess "+1" means "one more enemy if you miss"? Had expected some kind of score tracker.
I wasn't able to survive the final wave yet. Sometimes enemies spawn inside the floor, rendering them impossible to kill when their weakness is their feet. Maybe I don't get the weapon image, but to me it seems like it's aiming into the wrong direction.