Revealing mistake: After Jason's fight with Acastus, when Medea is telling Jason of the flower which can heal his wound, if you look past Medea you can see a mountain in the distance. On top of the mountain you can see a lighted building of some sort that appears to be a modern structure. (01:15:05)
Revealing mistake: During the fainting scene number of the extras can be seen waving and looking at the camera.
Revealing mistake: When the lady throws Sylvester through the window, you can see there is a bump on Sylvester's head before he hits the tree.