Cool concept. As other people have said, there should be a way to speed up the melting process maybe a x2 speed button when you're standing still, but other than that good job.

Interesting concept and I like the variety of level design. There are some areas that can be improved, like Makiki mentioned having a way to more quickly change size would be greatly appreciated, and at the 2nd smallest size it looks like you can fit underneath crawlspaces but you can't, there are some times when you get stuck in a ceiling when you grow into it and for one level transition I ran off a cliff because the previous level ended with a sprint to the end. But overall I very much enjoyed it.