Corrected entry: Someone as high in the police rankings as Hoffman couldn't possibly set up all the elaborate traps as well as kidnap all the victims without noticeably neglecting his law enforcement duties. He rushes the main traps of this film into motion, but the engineering on them alone would take days if not weeks to accomplish.
Corrected entry: When William escapes his first test and lifts his shirt up to see what the enormous bloodstain is from, he finds the surgical stitched-up would on his side, with a single stream of blood beginning to seep off of it, and the rest of his side is perfectly clean. The size of the wound, and the small amount of blood on his side contradict the enormous blood-stain on his shirt. If he was losing enough blood to create a stain that big, there should have been more blood on his side, either from the wound, or from the saturated shirt rubbing it on him.
Corrected entry: When Hank (the janitor) is killed, we see his white under-shirt being stained red with blood. However, as the blood flows out and begins to soak into his blue overalls/shirt, his blue clothes don't stain properly. While his white shirt turns red, his blue clothes simply get wet as if soaking with water, but don't discolor at all from the red blood. This reveals some sort of fake blood was used, as it doesn't "stain" properly on his darker clothes, only on his white shirt.
Corrected entry: In the opening "game" of the film, Simone is forced to remove flesh to stay alive. We then see her sever an arm with a few blows from a hatchet in order to win the game. The arm is removed about 3 inches below the elbow but a later scene in the hospital shows a bandage with the arm completely gone from far above the elbow. Furthermore, modern advances in limb re-attachment allow for a limb to be re-attached up to a full day after the accident. Why didn't the doctors in the OR simply re-attach the arm that had been lobbed off?
Corrected entry: At the beginning of the film, Hoffman retracts the walls of the room where Agent Strahm has been squashed. The whole body drops to the floor. However, Strahm's hand remains untouched. Now considering the walls shut completely, his hand would have not survived if they were powerful enough to crush his body.