When Agent Hartkamp loses her shoes, you can clearly see her bare legs and bare feet. Later when she enters the gym, she's suddenly wearing a pantyhose.
During the end fight, Arjen loses his cap. He forces Leonie to lose her cap as well and finally causes Wouter his cap to fall off. In the aftermath, all three caps disappear and reappear on the floor.
Lienke takes off her shoes, climbs up the wall on her socks and leaves the shoes behind. But in the next shot, both shoes are gone.
When Arjen and Rosa land on the bed where she tickles his bare belly, her bonnet falls off on the mattress and his cap rolls off the mattress. But in later shots, the cap is back.
Agent Hartkamp is knocked down by Lienke in the final fight and her hat falls off in front of her. Seconds after, when Lienke dives on top of her bare belly, her cap falls off behind them where suddenly the hat now also lies.
At some points, characters obviously stand in front of a poorly edited transparent green screen.
When Wouter climbs up the wall on his socks and loses his cap after looking down, the reflection of the cameraman can be seen in the window.
Lienke and Wouter support each other when they enter the gym by stretching up each others sweater and deliberately uncover their bellies. This is a very unnatural way of carrying someone.