I actually will play the game later again, because I liked it a lot! You made a really good job of introducing new mechanics and adding something new to each level.
I would recommend to make the slime more... slimish? Make him wiggle and change the form even more. And also, the rewind ability was on point, but I would really like to stop the rewind at any time, because otherwise, it seems as simply restarting the level. But hey, overall the game is cool, continue working on it!