The assailant decapitates a chicken in front of the hostage, which twitches slightly before it's dropped dead; in actuality, the chicken could still run around for a few seconds. This is because a neural network in its spine is pre-programmed to control the muscles in frequently-used movements such as running or swimming.
When the assailant decapitates the woman, it's clear that the head is not there and that he hits the bloodied stump; making it appear as if the woman was already decapitated.
The camera's shadow can be seen as it shows a view of a tank during the "Collection" scene.
When the woman gets chased by the assailant, the shadow of the assailant running reveals him holding the camera.
After the woman has been drugged again, the boom mic's shadow is momentarily visible on the bed.