Look, it's the third one, so you already know it's bad. And "Maniac Cop" wasn't good enough to warrant the second installment, so you know it's even worse. But how much worse? Awful, approaching God-awful.
When Maniac Cop goes on a killing spree, a reporter exclaims, "What happened here can ONLY be described as a black rainbow of death."
1-- Rainbows are not black, and can never be. 2-- Rainbows are harmless, and can never inflict pain or death. 3-- A news reporter, one valuable to his agency, might find another way to describe the aftermath of a killing spree. "A black rainbow of death" is not the ONLY way to describe the given situation.
This is what you're in for.