Other mistake: In the music within the ending credits, the lyrics incorrectly state that Raph is the leader of the group when all Turtle fans past and present know it is Leo.
Teenage Mutant Ninja Turtles (1990)
Plot summary
Directed by: Steve Barron
Starring: Sam Rockwell, Elias Koteas, Judith Hoag, Josh Pais, Michelan Sisti, David Forman
Four turtles and a rat are transformed into a humanized state by a mutagenetic gel called Ooze in a sewer. The rat becomes their mentor, and teaches them all he knows regarding Ninjitsu. The turtles use their newfound skills to combat the crime in New York City. But when their mentor is captured by an enemy from the past, Oroko Saki also known as the Shredder. Now can the turtles hold true to what they've learned, and stay together as a brotherhood?
More mistakes in Teenage Mutant Ninja Turtles
Michelangelo: God, I love BEING A TURTLE.
Trivia: At one point in the movie Shredder scolds Tatsu, and right after that, Tatsu curses saying, "kuso." That's about the equivalent of saying sh*t in Japanese.
Answer: Most likely to kill Shredder and make sure that there would be no way to come back but, as seen in the sequel, Shredder does return.