Ohhh, I hate that ball in Terraria! That last level was hell, but managed to complete it (after... don't know... 50 retries LOL )
Good concept, but kind of wasted I think. There were few living things to crush, which would had been funnier.
The controls are simple, but pretty hard to master, specially on the floating platforms. The ball has too much acceleration, so it makes it really hard when landing on small platforms and trying to stop the intertia of the ball giving just a small tap to the A key. Most of the times I use that technique on platforms games, but on this one when using it, I ended up falling off the platform.
Even with all this small issues, the game is still entertaining. Great presentation.
Great work!