In the game, the player is using rhythms and music to beat Dr. Hamsterviel on many levels. Here's what the game is about, taken right from the official press release:
"Disney Stitch Jam allows players to help Stitch take part in action-filled rhythm-based missions to defeat Dr. Hamsterviel in an epic galactic showdown. Players will become immersed in 10 visually stunning locations including tropical beaches, a frozen city, the deep forest and many more environments while jamming to the rhythm. Players will complete musical missions by dodging obstacles, gathering cool collectibles, slamming enemies and unlocking accessories and costumes to disguise Stitch and his friends. Once players complete story mode, they will be able to play in free mode as other fun characters from the world of Stitch including Angel, Reuben and Felix."
The game can also be a two player game with a download option, allowing two people to play together as Stitch and Angel. Disney Stitch Jam is rated E for Everyone and is about $19.99.