Seconding CHz — not only is this a cute take on saving vs killing the animals, but forcing me to learn each animal's ability by playing as the animal is really clever and not something I can remember seeing before.
I had an awfully hard time getting back as rabbit; I had to get back onto the screen with the falling frames without letting the leftmost one fall so I could jump onto it, and I could only barely make the jump. And that was after a lot of running around before figuring out I could jump through platforms, which I hadn't had to do before :)
Gravity also seems a touch high, which makes jumping a bit unforgiving — especially the timed jump just before the rabbit.
I do love this idea, though! I hope you really do Work On It More In The Coming Weeks™.