Yeah, the way it works is that when you buy the game, you get three characters with it, and the platform dealie they stand on. And you can beat the game with just those three guys. But as you play, you'll come across items that unlock special abilities for the various figures that exist. Not necessarily the ones you have. And when you do, it's all "do you want to see a preview of that guy?" And each new character you get unlocks a special challenge minigame that you can play with each figure to boost its stats. And there are areas within the game that you can only enter with a character of a certain type (fire, ground, etc.).
So if you never bought any other guys, you could beat it, but you'd be missing out on a bunch of content, and although they don't shove that in your face, they definitely remind you of it from time to time.
I'm actually surprised that nobody here has played it. My nephew and his friends love it, and the fact that they made more than one game (and that Disney is copycatting them) tells me they did pretty well with it.
