Revealing mistake: After Splinter releases the nunchaku from Shredder's spear, he falls from the building's ledge. But notice how Shredder stops abruptly right before the series of shots which show him taking the long fall into a trash compactor, indicating that he actually lands on a mat. (01:23:00)
Teenage Mutant Ninja Turtles (1990)
21 revealing mistakes
Directed by: Steve Barron
Starring: Sam Rockwell, Elias Koteas, Judith Hoag, Josh Pais, Michelan Sisti, David Forman
Audio problem: At the climax of the film when the Turtles are about to face Shredder for the first time, Raphael says, "I got him" and then runs to fight. When Raphael falls to the ground, his pair of Sai hit the ground but make no noise. There should be a metallic sound against the rooftop. (01:19:00)
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.