I missed the in-game instructions saying you need to hold K to stay transformed. Once I figured that out, I passed level 4 and 5 with just the frog. Transformed, jumped, transformed back and double-jumped to get the key.
An enjoyable game. I was on the last level when I had to leave home. I had to start from scratch.
Not sure what the spider on stage 5 was for though. I think the one on 6 is if you miss the key or ledge (or both).
For a jam game it's awesome. Quite short otherwise.