Great concept!
First off, the aesthetics are adorable. What an idea to have Patty the Platform escort the character to a comforting wall of pink goo.
It was very difficult. In some ways it felt fair; in others, not as fair. Perhaps this could be solved by making the player feel completely in control of their horizontal positioning? I mostly achieved this by bouncing the avatar to the left or right, which takes up vertical space, which can get you killed. That might be an intentional decision, though.
In the final level, with the two collectibles that are at about the same X position but one is higher than the other, I decided to just skip one of them. But then I found out I needed to collect it, and I panicked a bit. But I figured out the trick for getting it, and that felt nice. (I see now that you solve that problem in the GIF you uploaded)
I figure you are aware it doesn't have sound haha. That's probably the most obvious detriment.
Nice job!