Well done on making this so far. Had a nice bit of fun with it.
Visuals are okay. Theres not really too much going on visually, so not much else to say.
Controls are very fluid and responsive.
Took me a while to realize what I needed to do, but cool project all the same.
I havent been able to get the scores of the people below but did manage to shatter the core :)
I dont recall exactly what upgrades I picked, but I know that on my first run I picked a variety (such as the one that has explosions affect surrounding bricks, and the one that lets a ball pass through bricks) but on the run where I shattered the core, I stacked the upgrade that gives extra balls.
As for the wave, I think it was 13, but Im doing that from memory and it may be incorrect. It was only a single wave where I had the opportunity to shatter the core.