Dodgeball! It was really interesting, being able to use the balls as both offense and defense. I felt like each encounter with an enemy was a duel, and facing multiple was like a desperate escape!
The glass breaking mechanic was genius. It gave me the choice, for example, to keep my ball positioned at a group of foes about to corner me or to lower my defenses to open an escape route. This is definitely something you could expand on a ton! (variably charged shots, killing off wall-bounces, etc.)
One thing I'd offer for feedback is that after I found myself cornered, I was kinda just toast. Maybe you could explore ways to give the player leeway in those situations. Maybe a close range attack option, or a minimum distance the enemies can walk towards you, etc. I'm sure there's lots of neat ways you could solve that problem!