Slayground (1983)

Stone (Peter Coyote) hits an armored truck without his usual driver. The ensuing getaway leads to the death of an innocent. The payback is swift and brutal. The wronged father hires a twisted, sociopathic assassin to avenge his loss. One by one the offenders are punished through grisly executions. Stone uses his wits to find a reclusive friend Terry (Mel Smith) just in time for a psychedelic funhouse showdown with his stalker.