Revealing mistake: When Paul Kersey blows up the restaurant, there are obvious dummies in the booth. (00:46:01)
Revealing mistake: When Frank Bauggs is fighting Paul Kersey, in the shot where Frank is about to run through a window you can see that the window is cracked just before he goes through it. (00:50:40)
Revealing mistake: When Frank Bauggs is falling from the building, he is a very obvious dummy. His body limps around too much. (00:50:45)