Revealing mistake: During the final battle in hell, when the army of Spawns rise up, there are some small errors to look for. First, during a few shots where the army is closer to camera, you can see the CGI army becoming "pixely." Also, you can see at least one of the Spawn floating in the air, not standing on the platform with the rest of him. Problems with the CGI rendering/animation.
Revealing mistake: When the paramedics are covering Zack's dead father's head with the blanket, his left eye briefly twitches. Note: timecode refers to the director's cut. (01:05:19)
Chosen answer: He is squatting the entire time in every scene. The suit probably helped in ways to balance himself whilst squatting, so he could hold on much longer than normally.
lionhead