Really cool idea! If every form had its own unique abilites and there were many puzzles involving switching between forms - I'd play that!
I had a few problems while playing. First, I straight up wall jumped over the wall to the right when you start with the ball form so I was confused what to do when it came to getting the cat. I didn't even think of going left at first! :D The snail sometimes got stuck in the little passages and it was annoying to get it through (also when you go through the passage to the next level and come back in a different form you start stuck inside the ground). When you get to the most left side of the level with the bunny and jump, you jump out of the game and can't do anything but restart :/ When I got all forms it was really difficult to switch them. I had to look up which number is which character, then press that number and if it was a higher number (like 7) I would have to look it up on my keyboard. Took lots of unnecessary time. A select menu or select wheel would be so much more comfortable!
Overall, I love the idea. I wish there were more abilities and that the levels were longer and more challenging. I want to play more! :D