Does *Earthworm Jim *count as a shooter? God, those kicked ass. Are we ever getting another one?
Sticking with the usual definition of scrolling shooter, I have always had a fondness for the Star Soldier series. As a close second I’ve found that the Parodius spin-offs of Gradius were better than the original.
And regarding Flashback, don’t overlook the sequel Fade to Black. It doesn’t play the same as the original but I found it a good game in its own right.