Yeah, I think the comedy and violence mix works out pretty evenly on this one, as it's so well compartmentalized. The violence has its own lead character (badass Mafioso Van Cleef) and its own music (the somber, minor-key horn music by Riz Ortolani). Likewise, the comedy has its own lead character (Mafia wannabe Lo Bianco) and its own music (the bright, major-key horn music by Ortolani).
What's more, the movie has some good murder set-pieces, like when the guy gets stabbed in the photo booth, and then that little strip of pictures emerges from the slot, recording the victim's death face.
And yeah, there are SO MANY English-language releases for this movie. The ones that made it to home video are MEAN FRANK AND CRAZY TONY and ESCAPE FROM DEATH ROW (the latter of which has a bunch of bogus credits and removes the drill-kill scene). My friend saw it back in the '70s in the U.S. as POWER KILL. And I've also seen posters for it as THE GUN and GANGSTER STORY.