Peter Criss was dubbed, because he wouldn't show up to do looping (re-recording lines in post-production). His voice was dubbed by voiceover artist Michael Bell, who did a lot of work for Hanna-Barbera.
According to Paul Stanley in VH1's "KISS: Behind The Music", Ace Frehley often failed to show up during shooting, so Ace's stunt double, an African-American, had to act in some scenes and fill in for Ace on some of the fight scenes. The stunt double's voice was overdubbed to sound like Ace (there are differing versions as to whether Ace or a sound-alike did the overdubbing).
The cartoon-style music that appears during fight sequences was added after the production team realized that the film needed a lower certificate to enable younger KISS fans (the majority) to see the film.
Kiss, nearly broke up after the film because, Ace Frehley and Peter Criss were increasingly unhappy. Their manager, Bill Aucoin said to the band to split temporarly and record solo albums. Ace's album had outdone, the other three with a top single.
When this was originally shown on "NBC Saturday Night at the Movies", on October 28, 1978, the opening trailer bumper was announced by New York NBC staff announcer Fred Collins, while Peggy Taylor, one of the network's Burbank-based staff announcers, did commercial and ending bumpers.