If you weren’t turned off by the bad guys’ complete inability to hit Banderas in the barroom scene, despite having superior numbers and weapons, I don’t see how you can be turned off by a rocket launcher in a guitar case.
I, myself, start falling asleep everytime I watch Desperado some time right after Buscemi dies.  For me, the movie peaks out somewhere between that scene and the bar scene, and despite the increased explosions and violence, it never quite reaches that perfect mixture of decent story telling, adrenaline, and testosterone, again.
