During the scene where Jeffrey is about to purchase a knife in the sporting goods store, a boom microphone is visible at the top-center of the screen. This occurs right after the store clerk says "I ain't even messin' it up."
When Dahmer is sitting in the lunch room of the chocolate factory, the establishing shot shows three chocolate men standing in a row in front of him. In the next shot, the chocolate figure on the right has fallen down.
The opening title card indicates that Jeffrey Dahmer was sentenced to 957 years of federal prison. This is inaccurate. Dahmer was convicted of 15 murders in a state trial in Wisconsin and served his sentence at Columbia Correctional Institution, which is overseen by the Wisconsin Department of Corrections.
The uniforms for the Milwaukee Police officers are incorrect. The badges and cap shields are L.A. style and the officers are wearing shoulder patches on both shoulders. Milwaukee officers wear a patch only on the left shoulder.