Raiden Fighters, Raiden Fighters 2, and Raiden Fighters Jet
Pretty much every shmup fan knows how influential the Raiden series is on the genre as a whole, and now, a bulk of it is available on the Ouya. Developer and publisher DotEmu has just released the Raiden Legacy pack, which includes four games: Raiden, Raiden Fighters, Raiden Fighters 2, and Raiden Fighters Jet.
It also includes the ability to turn auto-fire on or off, two video modes, and three gametypes (arcade, mission, and training). In true Ouya form, the first stages are playable for free, with the option to buy the full game for $3.99. While it may not be as excited as a brand new shoot-'em-up on the Ouya, it may give you something to do on the thing.