After the fairgrounds battle, an EKG monitor is seen, scanning screen right to left. This is followed by the EKG's reflection in Carrie's glasses, also moving screen right to left, instead of left to right.
The automated missiles set to target Superman during the final confrontation have a misspelled readout, "X-RAY DECTECTED."
the mug the Joker uses has Endocrine spelled "ENDOCHRINE"