A Fistful of Gun is a combination of a classic beat-'em-up like Turtles in Time and a shoot-'em-up like Jamestown. So naturally, I'm deeming it a sheat-'em-up.
No, wait, that sounds terrible.
A boot-'em-up? Better, but still not that great...
How about a boosh-'em-up? Yeah, I'll go with that one. A Fistful of Gun is the best goddamn boosh-'em-up of all time.