Character mistake: In the third instance where Superman manages to get rid of Mxyzptlk, he uses an article full of typos which spell the latter's name backwards as KLTPZYXM. Among the incorrect words is the word "citrimes", in which Superman has included an I and a T, so the correct word in context with the rest of the text should read "crimes" and thus the errors would spell KL-I-TPZYXM. Since there are no vowels in MXYZPTLK, however, what is the additional I doing here - and why didn't Mxyzptlk bother to mark it as a mistake, either?
Character mistake: Throughout the series, General Ross refers to Gabe Jones as Gabriel. Someone of Ross' military credentials would not address another government agent by their first name. He would call him Agent Jones or simply Jones.