 When playing easy mode, Splinter will tell you to challenge the normal mode  when you defeat Shredder. In normal mode, Splinter will tell you to challenge  the hard mode in order to be true ninjas. In the hard mode, it features the  turtles flying the State of Liberty back to its normal place via the Turtle  Blimp, followed by the credits rolling while the turtles wave and smile on  the Blimp, then the cast of game characters roll, then Splinter says you are  now true Ninjas.