Visible crew/equipment: At the beginning of the movie, as the hanging prostitute's corpse is dragged along the roof of the boat under the shocked eyes of the tourists, the shadow of the camera is visible on the seats as it passes on them.
Other mistake: Amazing how quickly the killer, armed only with a butcher's knife, could behead a guy under water before killing the other one.
Other mistake: Amazing that nobody sees the hooker's dangling body before that boat tour which looks like it's around nine, plenty of time for somebody else to notice her.
Other mistake: The hooker's killed on dry land, bloodied before being dragged into the water yet she somehow has dried blood on her face when discovered.
Other mistake: When translating Dutch for English, one translation uses "their" when it should've been "there." It's in the scene when we first see the lead cop talking to his daughter.