Various General Tips
Unlocking new cats won't give you any special abilities, but it might unlock new mini-games.
To unlock them, you will need coins, and you can get coins simply by watching ads on the main page, next to the coin counter.
Of course, you can also get coins by replaying old levels and achieving better results.
You need 100 coins to get one of those plastic balls with the new cat character inside.
As you play the game, you'll realize that the speed is one of the most important things in it. You don't need to be all that precise if you can reach some decent speed through the mini-games.
Since all of the mini-games are different, you won't be able to use one strategy for them all. Instead, try memorizing what every one of them is all about.