For your 3rd Unity game, this isn't bad at all! How long did it take you to create this is one of my big questions. But anyways, I have only a few criticisms to put against the game. The controls are not bad by any means, by the latency and responsiveness is something to be improved upon, along with the rolling psychics being a bit too slippery at times, causing the player to fall into lava. It could also use a bit more, perse, "personality" (I.E. backgrounds for stages, maybe some music if there's not already, and a bit more "movement" to the character of Mr. Round Man.)
Also, the gameplay could use maybe...a pause menu by chance? That would be immensely helpful if you're switching tabs.
Other than that, this a solid, and simple, game that's currently under judgement. Good job on this Unity game, and I hope to see more from you.