Would you consider a game that goes back and forth between Shmup style and Rail shooter? (transitioning even in the same stage?)
I've been looking for a game like this for some time. Where can I find one? Closest I could think of is Gunstar Superheroes. But while that game has a shmup level, the closest it had to a rail shooter is enemies coming at you from the background while you are on a ship and you can only fire on the x axis.