Deliberate mistake: Laser beams are normally not visible, except for a small dot where they hit a surface. Even if made visible, using smoke or dust or special glasses, they are thin as threads. Obviously something more visual was needed for Toulour's dance act, hence the thick beams of light.
Deliberate mistake: When Lazlo is hiding the dollar bill in the painting, look closely and you will see the scene is played backwards. Ashes from his cigarette flies back up and smoke from the cigarette comes down. (00:22:35)
Deliberate mistake: Slavo and Dragan are supposed to be Serbians but they speak Romanian.
Deliberate mistake: When Dwight Yoakum is being shot by Rita, and he is holding Lew, you can plainly see Lew has earplugs in to muffle the gunshot.
Deliberate mistake: When Reese is looking at Starsky and Hutch's police profiles, his brunette girlfriend says, "Ooh, he's cute, the blonde", referring to Hutch. From the way she says it, it sounds like she's referring to the picture, however you cannot see Hutch's hair in the picture. She had not previously met Starsky and Hutch, either, as it was Resse's blonde wife that was in the room at the time. (00:28:40)
Deliberate mistake: When Saint is being dragged through the parking lot with all the exploding cars, there are a few shots where it is obviously just a dummy instead of John Travolta (the actor who played Saint).
Deliberate mistake: Perhaps to avoid getting an R rating or parental complaints notice how in the operating room massacre none of the doctors appear to bleed nor do Doc Ock's tentacles have blood on them.
Suggested correction: The problem is in both versions of the film, basically all of the deaths either happen off-camera, or are things like people being shocked to death or killed by being tossed around and presumably having their backs/necks broken. Most of the deaths would be bloodless or near-bloodless anyways, and the camera simply doesn't linger on the bodies enough to show any blood. This is also why the tentacles aren't really bloody. Sure, it was probably ratings-related, but it isn't technically a mistake.
Suggested correction: Talour would need to see the beams in order to get through. I would attest that he let off a low grade smoke canister with a fine mist like a concert hazer to make the beams visible yet not trip a smoke fire detector.