Everything gold Seth Rogen touches turns to mold. It's as if he knows nothing about TMNT and just did some small research in time for the movie. Mutant Mayhem is an unfaithful adaptation. Here's why:
Characters:
They were the worst part of the movie. The turtles pretty much act the same which is proven by how Donatello is no longer the smart nerd who likes making gadgets and sounds too young. Michelangelo is pretty much not a party animal who takes things unseriously. Leonardo is as silly as the rest of them and only showed one ounce of leadership during the final battle. Similar thing with Raphael who had only a few moments of hot-headedness. Splinter is no longer a martial artist who trains the turtles and is also not Japanese. They couldn't even make him a pet rat of Hamato Yoshi yet insist on having Shredder in the sequel. Not to mention how lazy he was for most of the movie(getting the turtles to run errands for him and only doing something after they get captured by Cynthia) Their training gets replaced by them watching fighting videos. I wish Splinter was still the wise sensei/father figure we all know. It's terrible way to modernise TMNT. The villains themselves sucked. The movie had some of the most popular characters like Leatherhead, Bebop and Rocksteady, Superfly/Baxter Stockman who were ruined. Leatherhead is now a female and an Australian crocodile, Bebop and Rocksteady aren't hired guns and were pretty much sidelined. Baxter and Superfly are now seperate, Genghis Frog no longer works for Shredder and Wingnut is now a female and finally, Scumbug is a female. Additionally, there are no human to mutant characters which mattered a lot to the franchise, just left to be teased by Superfly.
All the villains(except for Superfly and Cynthia Utrom), turn good which really punts a dent on future antagonists for the sequel.0
Comedy:
The second worst part of the film. Mutant Mayhem relies on terrible pop culture references and repeated jokes such as mentioning Attack on Titan, Beyonce, Drake, Godzilla, MCU and abusing April vomiting along with the turtles being milked joke. If anything, the movie should have been called "Attack on Turtles" since how much they butchered TMNT.
Some of the songs didn't fit with the scenes like Superfly's army on the road or Splinter fighting. The pacing made the movie feel rushed. The movie's action is quite low. Finally, the dialogue used words like "sus" and "rizz" which was just cringe and they never even once said "cowabunga". Also, Michelangelo twerks.
The artstyle was ugly most notably the humans. The characters looked like bad clay sculptures.