With ten different characters to learn the mechanics of, you might think that it will be hard to get the hang of everyone, but it's actually pretty easy; since the same buttons call up the same type moves, it's not like you have to completely change your mindset for new characters. All of the characters are moved around by using the D-pad. The (B) button is always jump, and, in the case of
Plankton, you can press it twice for a double jump. The (Y) button will let you attack. Everyone is going to have their own unique attacks, though, so you'll need to test them all out to figure out how they work and how close or far away you need to be from the enemy.
The thing that really differs from one character to the next is their special attack, although you always use (A) to launch it. For some characters, it is a more powerful attack; some can fly through things, some attacks can be used to get to higher areas. You'll quickly find your own style to use each character's abilities. When you want to switch from one character to the other, you use the (X) button.
When I first got this, I was expecting to play it through, write a review, and never pick it up again. I am pleased to report that I will be picking it back up when I get time. There is enough content to keep you busy for a while, especially trying to get the entire bonus content. I recommend buying it, not just renting. It's a wonderful game that will keep you entertained for hours.