Character mistake: When Curtis and Connie stop at the first gas station, the word diesel is misspelled as disel.
Character mistake: Both in the movie (and stage) versions, Mushnik makes a verbal mistake. Seymour shows Mushnik his new plant (Audrey II) for the very first time, but seconds later when the plant suddenly droops, Mushnik asks Seymour, "Why is it always wilting like that?" Always? He's just seen the plant! The line should be, "Why is it wilting like that?" Some smart stage directors of the play version have wised up and changed the line.
Character mistake: Given how smart the lead is he doesn't seem to know the proper dosage of sleeping meds he put into his mother's coffee. He placed in enough to possibly cause an overdose.
Character mistake: When Brenda first witnesses Connor and the Kurgan fight, Kurgan says "I am the only one." Afterwards, Brenda asks "What does he mean by there can be only one?" She somehow misheard Kurgan and thought he said the movie's iconic catch phrase.
Suggested correction: This is incorrect. He does say "There can be only one." He's saying it while beating Conner, so the first part is a little muddled and he emphasizes "one", but he does say the line.