I am currently working on an endless run game. The main character is a little pink cat which can jump and transform to another special cats. Currently there are only two special cats in my head. The first is Superman Cat which can fly and the second is Ninja Cat which can pass trough spikes or maybe monsters without getting hurt. I am currently searching for the third transformation. Actually there a lot of characters idea in my mind like maybe a spiderman cat, goku-cat (Is it illegal?) and swimmer cat which can swim. I have designed the character. You can see my character design here http://nineheadgenasha.blogspot.com/.

I am using LibGDX and Box2D. I have created some games for my homework and an educational game for a company(currently in testing) . I am still in college, currently on my third year. Critiques and suggestions are really welcomed.

You are on the right track. First off, try to think about challenges first, while keeping a skill in mind and assign it to a special cat afterwards .

Eg. I need long jumps to overcome certain challenges, so the superman cat can jump over large obstancle, still it is a skill (timing). The ninja get invisible for a short duration if he throws a smoke grenade in front of him (skill: you need to walk through smoke cloud when it explodes).

Other ideas:

- A furry ball (juggernaut cat), which can't be controlled but pushes through certain obstancles.

- A grapple-hook (burglar cat), which can shoot a grapple hook and swings over a chasm.

- A digger (miner cat), which can dig into the earth and undermines certain obstancles.

Btw., thought not my game style, your game looks nevertheless good so far.

If it will be endless game I would remove the superman cat. It will take away the challange.
Except if the transformation comes with a countdown

This reminds me of a game from the BBC micro days.

Can't remember the name of it.

But you could change between a cat (could jump) a mage (fire spell) something else and a bird (could fly)

You had a limited number of changes, 95 I think. When you ran out of changes, the game was over.