Continuity mistake: When Wynn is talking to Al about the mission to blow up the plant, Wynn puts his cigarette out in the ash tray in the scorpion bowl and there are 4 butts in the ash tray, but a minute later when the camera shows the 2 scorpions fighting, the ash tray has no cigarette butts in it. (00:11:19)
Continuity mistake: When Spawn is fighting with the clown, who is in his big reptilian monster form, Spawn is thrown against a fence with pointed tops. He is impaled against them, but the ones right next to him are shaking as if they were made of rubber, not of metal. In the next shot, the spikes are stiff and solid and made of metal.
Continuity mistake: When Cyan is given the clown doll at her party, it spins around and spits (or breaths) the green stuff and stops, but immediately in the next shot, the head has made a 180 Degree spin, which is impossible in that time.