Plot hole: When Dudikoff gets Ninja training from the old gardener before his final confrontation with Black Star Ninja, the gardener says "The time has come for your final lesson" and then introduces him to the throwing star and the ninja sword. If this is the final lesson and he's only being introduced to these weapons now, how come Dudikoff used these weapons successfully earlier, against about 15 ninjas in the fight at the warehouse trap?
Suggested correction: The lesson was the use of "ninja magic" symbols, not the weaponry.