Easily one of my favorite games. Bit trip runner was a solid game in a group of six games. Bit Trip Runner 2? Takes that single game and polishes it to the point that it can stand on it's own and it does.
Take fantastic music, amazing gameplay and a fair but challenging level design and you have a great game. The visuals are a joy to look at as either the player or an on looker, the sound is great, and the player will be playing in time with the music.
There's a reason when I have five or fifteen minutes to play a game, I'll throw on Bit Trip Runner 2. There's also a reason 60 minutes later, after my friends are ready and annoyed at waiting, I'm still taking one more attempt to beat the level I'm on.