The nice thing about the game is that the songs are not locked. What this means is that you can play any of the songs at once, without having to "unlock" them by performing to a certain standard. The game basically has you swiping, tapping, or drawing patterns on the screen in order to make the Michael Jackson avatar move to the beat, so you essentially need to be able to hear the song in order to play. That means headphones are a must, since the Vita's tiny speakers aren't going to give you high videlity.
The songs are great. This is Michael Jackson, so you'd expect it. I'd not heard a lot of the songs before, so this was my introduction to some of the other songs in his opus. I did not expect to enjoy songs like Smooth Criminal or Billie Jean, but I did. The game comes with 3 difficulty settings, but alas, I'm not so good a gamer that I can make it through the hardest difficulty setting. Along the way you get to win trophies, medals or other in-game awards to keep you coming back for more, but the songs are the main thing in a music/rhythm game and this game delivers.
As a handheld experience, this game's ideal, since each play lasts only as long as the song. The boot up experience takes quite a while though, and as some have mentioned, the game's scenes are rendered rather than using the original Jackson videos as backdrop, so you do lose a little bit. (The rendering is essential so the on-screen avatar matches your taps and swipes)
But heck for $8? Just buy the game. It's fun.