Just a few minor things I've picked up on :
-The way jewels shrink before vanishing, after you grab them, looks a bit odd to me ;
-I feel the characters could use to stand out a bit more against the background stuff. That grey character especially, seen in the Ice Cream level (0:14), blends in a little too well in my opinion. Maybe some outlines could do the trick? Then again, it might clash with the artstyle.
In any case, good luck with whatever is left to do