The "Teenage Mutant Ninja Turtles" franchise has certain built-in limits that make the stories it can tell a bit repetitive, especially in movie form. Over time, the franchise has constructed a series of tropes that every version of the story needs to hit, from the turtles' rough personality outlines to certain villains they have to face. As such, the movies we've seen so far tend to portray Leonardo as the leader, Raphael as a wild card, Donatello as a comparatively level-headed and smart gadgeteer, and Michelangelo as the relaxed, kid-friendly comic relief. They live in the New York City sewers, love pizza, have difficulty interacting with the outside world due to their appearance, and you just know that they'll face the Shredder at some point down the line ... usually multiple times per movie series.
The turtles aren't the only fictional heroes beholden to a stiff set of rules — just count the big beats every Batman movie hits regardless of who might be sitting in the director's seat. Still, at this point of the "TMNT" franchise's lengthy tenure, it's kind of disappointing that the only movie that's attempted to shake things up is "Teenage Mutant Ninja Turtles III" with its "Let's drop them in feudal Japan and see what happens" premise. It remains to be seen how much "Teenage Mutant Ninja Turtles: Mutant Mayhem" manages to address the issue, but since it once again tells the story of the titular heroes' first adventures out of the sewers, it may very well be that whatever shake-ups it attempts will be largely cosmetic.
"The Last Ronin," on the other hand ...
