Not bad.
It was abit repetitive, but then again most games like this end up as timewasters. It actually felt like a decent Sonic spinoff game that you would find on the GBA, mainly due to a Last Story unlocked by getting the emeralds.
The controls were abit meh, and I felt that it might've done well with a stat screen to tell you how the physics affected certain characters.
Outside of that, this was a really good game given it's a basic "Launch shit out of a cannon and see how far it goes" game.