Pokemon developers Game Freak are making a new rhythm action game for 3DS. Called Rhythm Hunter: Harmo Knight, Game Freak's new game was unveiled during Nintendo Direct.
Juding by this trailer It's a rhythm action game from the Bit.Trip Runner school as it's a side-scrolling game in which you have to run along, collect notes and whack enemies with a quaver (not the cheesy potato snack). If you manage to do this smoothly, a nice tune will play. That's Harmo Knight at its most basic. As you can see from watching this trailer, it gets a lot more challenging as things speed up.