I agree with the other reviewers about how responsive the movement felt and I didn't find any issues or bugs.
It's a simple game and it could use sound, some effects to make it juicier like maybe effects or particles that come out every time the cube hits a wall. The enemies and level designs could be a little more challenging.
Overall, Tumble does tumbling well. You tumble through to the end, collecting crystals and then you win :)