Fun entry, the platforming was pretty good, it's a bummer you ran out of time for the actual metamorphosis but that's how these things go. Keep at it and you'll get better each time (though you'll need to resist making bigger games!).
I liked how attacking worked, it was like I had spike shield which is cool. Having some effect when you took damage would be helpful. Initially I didn't realize I was getting hurt since I wasn't looking at my health.
Having the intro was awesome, but I'd definitely have a way to skip it.
You might try desaturating the background, all the colors are on the bright and saturated side so you have to think about what the platforming surface is.
These are just some ideas for next time, or if you continue working on this. Regardless, great job!