History YMMV / TeenageMutantNinjaTurtles2003

** ''Fast Forward'' shifted the Turtles to the future and went for a more [[LighterAndSofter lighthearted]] tone, which alienated fans who preferred the prior seasons, but the season often referenced plot points and characters from prior seasons who understandably [[PutOnABus weren't present]] due to the shift in setting (or in the case of Bishop and Baxter, were present), which left it [[ContinuityLockout difficult]] for newer fans to get into.

** Torbin Zixx from ''Fast Forward'' tends to be rather disliked by fans due to all three of his appearances largely boiling down to conning or swindling the Turtles.

* ContinuityLockout: The series didn't adhere to StatusQuoIsGod, which resulted in a lot of long-running plot threads, major reveals that often end up casually conversed about, and bits of character development from episode to episode that people won't catch unless they watch avidly.

** The fact that despite being a genocidal maniac who wanted nothing more than to return to the stars to begin his conquest anew, Ch’Rell still decided to take in, raise, and train an orphaned human girl out of no reason other than simple altruism. This has left an impression on fans years after the series ended as they were left to debate his intentions and what this says about even the most vile incarnation of the character to date.

** Season 5 is divisive: many people felt it did a good job wrapping up the remaining plot threads from the previous season, while others felt it was overly gimmicky and too much of an anime[=/=]''[[WesternAnimation/AvatarTheLastAirbender Avatar]]'' ripoff, abandoning the series' original roots of being influenced primarily by the original Mirage comics. All that being said, Season 5 is still much better received compared to ''Fast Forward'' and ''Back To The Sewers'' due to having a DarkerAndEdgier plot in the form of the Demon Shredder, exploring the martial arts lineage of Master Yoshi and The Ancient One in the Ninja Tribunal, maintaining the same level of animation and artwork from the first four seasons, giving final closure to the Master Yoshi subplot, and generally having an epic SeriesFinale feel to top everything off.

* DracoInLeatherPants: Agent Bishop gets this treatment from a large portion of the fanbase. While he does change his ways and brings peace and stability to the Earth in Fast Forward, he still committed a lot of evil deeds in the bulk of his appearances, most notably attempting to dissect the Turtles and Splinter multiple times, torturing Leatherhead, ruining the lives of his own men by mutating them into monsters, and torturing countless sentient alien beings in the decades leading up to his ultimate HeelFaceTurn. Even though there's little doubt that Agent Bishop is a complex character and multi-faceted AntiVillain who himself was experimented on by aliens during the Civil War and thus, has a [[FreudianExcuse sympathetic and believable motive]] for wanting to keep Earth safe from aliens invasions, a lot of his fans still have a tendency to play down all his evil deeds and romanticize him as little more than a noble and selfless HeroAntagonist who only has the best interests of the world at heart, even though many of his pre-Fast Forward actions show that he's NOT(most notably when he openly admitted to Splinter in "Bishop's Gambit" that he honestly doesn't care if innocent people get killed by his Slayers in his quest to root out aliens). What also helps his case is that Bishop tends to be given a free pass by many fans for acts that they would crucify other villains for. When Karai tried to kill the Turtles and Splinter in ''Scion of The Shredder'' in an assault on their home, fans were about ready to lynch her. However, when Bishop did something similar in ''Bishop's Gambit'' by forcing the Turtles out of their homes with sonics, kidnapping Splinter, and trying to have the Turtles killed, fan reactions to his ruthless actions were much more muted, if not totally silent, by comparison.

* FanPreferredCutContent: While ''Fast Forward'' is considered to be a divisive season, many would have preferred a second season to it compared to what ''[[SeasonalRot Back To The Sewers]]'' brought as it would've featured Ch'rell taking over the body of a dead Triceraton soldier which would've likely had ''Fast Forward'' to be more in-line to the earlier seasons.

** Leonardo accidentally stabs Splinter in his nightmare in “The Darkness Within”. Come “The Ancient One”, he ends up ''actually'' injuring Splinter after losing his temper.

** In "Hunted," Leatherhead shows deep care for Michelangelo when he accidentally hurts him [[spoiler: and is extremely happy when he Michelangelo alive and well]]. Fast forward to [[WesternAnimation/TeenageMutantNinjaTurtles2012 the 2012 series]], where the two become best friends.
** In "Tale Of Master Yoshi," Leo spoke fondly of Tang Shen, since he states Yoshi’s story is about "a girl." Come ComicBook/TeenageMutantNinjaTurtlesIDW and you see [[spoiler:Shen and Leo being mother and son respectively, especially when the former comforts her older son in spirit.]]

** In "Exodus", it was promised "[[WhamEpisode One of these characters will never be seen again.]]", and after the episode, Ch'rell is banished to an ice planet, likely never to be seen again... That is, until ''WesternAnimation/TurtlesForever'', but even before that, Peter Laird confirmed that the Triceraton Shredder shown in concept art of a possible second ''Fast Forward'' season would have been Ch'rell hijacking the body of a Triceraton soldier, and ''Back To The Sewers'' not-so-subtly implied in its first episode that Ch'rell would fight the other two Shredders in the show (there would have been an arc called "The Shredder Wars"). Making the claim that Ch'rell would never be seen again ''hysterical''.

** Related to that, April gets to meet Usagi in the show's ChristmasEpisode. Creator/VeronicaTaylor would later be cast as an ally to that other Usagi as a fellow Sailor Guardian.
** Michelangelo is voiced here by Creator/WayneGrayson. Later on, the Turtles meet the Dynamic Duo in ''ComicBook/BatmanTeenageMutantNinjaTurtles''. (granted, the Robin in that series is Damien Wayne, rather than Dick Grayson. Grayson does appear, as Nightwing, in Vol. 2 and as both Robin and later Nightwing in Batman/Teenage Mutant Ninja Turtles Adventures)

** Mikey is a superhero fanboy who becomes a superhero himself (specifically a BadassNormal in a show full of powered hero, meets numerous superheroes (including Nobody, who bears a superficial resemblance to Batman), and becomes a reserve member of the Justice Force. Fast forward to the Nickelodeon era and the TMNT have crossed over with Batman multiple times.

** While the “Fast Forward” season was maligned for many reasons, a substantial amount of the blame is still heaped upon [[CousinOliver Cody Jones]], due to how he was basically TheLoad added to the existing team dynamic of the turtles and Splinter, with most of the Fast Forward episodes based around him being a turtles fanboy and his uncle conspiring against him. He got more competent later in the season, but this lead to people having the opposite complaints—Cody became the one who ended up saving the day more often then not (especially in "Day of Awakening") which got him labelled as a CreatorsPet to some extent.

** The Rat King's appearance in "I, Monster" hints he'll reappear, but afterwards only cameos in the finale to ''Back To The Sewers''.

** Some of the ideas in ''Back To The Sewers'', such as the one-year TimeSkip, could have had interesting ramifications if they were properly explored.
** One of the fantasy warriors from Kirby's world is seen at the Battle Nexus. The show likely was reusing an animation model, but some fans would have liked if he genuinely was from Kirby’s dimension and if this could’ve led Donatello to reconnect with Kirby.
* UnpopularPopularCharacter: To the Turtles, Splinter, Leatherhead, and many protagonists in modern times who know of his existence, Agent Bishop is hated and reviled, and for good reason, based on the number of times he's tortured them, kidnapped them, tried to dissect them, and generally made their lives miserable. Even in Fast Forward when Bishop has finally made the turn from villain to hero and is popular with the general populace, the Turtles still have an abrasive relationship with him at best, with Raphael in particular usually making snide remarks and taking verbal jabs at Bishop. To a lot of fans, however, Agent Bishop is bar none [[EnsembleDarkhorse THE best character created for the show]] and has gone on to become perhaps the most iconic villain of the TMNT franchise not named Shredder. Him being a big enough hit with the fans was such that his character eventually became a CanonImmigrant to the IDW Comics and the 2012 TMNT show.

* VindicatedbyHistory: While the viewpoint still remains far from universal, the reception to Shredder being an Utrom has improved with the passage of time. As the reveal elevated the villain's potential from a human criminal mastermind with an army of ninjas to a cosmic-level threat capable of bringing the universe to its knees. In particular, it's not uncommon to note that Ch'rell is almost an amalgamation of Shredder's skill and strength as a Ninja combined with the intelligence of a much more sadistic Krang. Also with how ridiculous the TMNT franchise has become across its various incarnations, the idea of Shredder being an alien is simply no longer as unusual as it once was. Even those who still aren't fans of the idea will admit that, looking back, this version of the Shredder still has a lot of other traits they want to see out of the character.

* SignatureScene:
** Season 1: From “Return to New York, Part 3”, despite having been decapitated by Leo, the Shredder’s body gets up, picks up his severed head, and walks away just fine.
** Season 2: TheReveal of the Shredder’s true nature in “Secret Origins, Part 3”, and then the final showdown with Drako and the Ultimate Ninja in “The Big Brawl, Part 4”.
** Season 3: Bishop handily fighting off the combined forces of Hun, Karai, and the Turtles in “Hun on the Run”, establishing him as a credible third party in the show’s conflict; the climax of “Same As It Never Was” in which the BadFuture counterparts of most of the cast perish (including the Shredder who meets a particularly messy death at Donnie’s hands); and the scene in “Exodus, Part 2” where the Turtles and Splinter agree to perform a HeroicSacrifice to stop Shredder.
** Season 4: Leo’s TheReasonYouSuckSpeech to his brothers and Casey in “Dragons Rising”; Leo harming Splinter in a fit of rage and later finally making peace in “The Ancient One”; and the cliffhanger ending of “Ninja Tribunal” (which notoriously went unresolved for two real-world years for fans in the U.S.).
** Season 5: The epic scene where the Turtles lead forth an army of their allies and enemies to attack the Tengu Shredder’s fortress in “Enter the Dragons, Part 1”.
** Season 6: Darius’s last ditch attempt to kill Cody in “Turtle X-Tinction!” with Serling giving his life (temporarily) to stop him; Dark Leo reflecting on how he’s been changed for the better at the end of “DNA is Thicker Than Water”.
** Season 7: The “Shredder War” briefly seen in “Tempus Fugit”; the final scene in which Casey and April are married, watched by all the characters of the series.

** In ''Turtle X-Tinction'', the group sees a clip of a much younger Cody happily interacting with his uncle Darius Dunn... who in the present has already tried to kill him. As the clip is brief and Dunn seems genuinely happy while playfully ruffling Cody’s hair, it’s completely left to the viewer to wonder if there was a time that Dunn ever had any genuine love for his nephew, or was just being nice in a PetTheDog moment (which also raises questions if Dunn treats young children any better than, well, literally anybody else).

* VindicatedbyHistory: While the viewpoint still remains far from universal, the reception to Shredder being an Utrom has improved with the passage of time. As the reveal elevated the villain's potential from a human criminal mastermind with an army of ninjas to a cosmic-level threat capable of bringing the universe to its knees. In particular, it's not uncommon to note that Ch'rell is almost an amalgamation of Shredder's skill and strength as a Ninja combined with the intelligence of a much more sadistic Krang. Also with how ridiculous the TMNT franchise has become across its various incarnations, the idea of Shredder being an alien is simply no longer as unusual as it once was.

* VindicatedbyHistory: While the viewpoint still remains far from universal, the reception to Shredder being an utrom has improved with the passage of time. As the reveal elevated the villain's potential from a human criminal mastermind with an army of ninjas to a cosmic-level threat capable of bringing the universe to its knees. In particular, it's not uncommon to note that Ch'rell is almost an amalgamation of Shredder's skill and strength as a Ninja combined with the intelligence of a much more sadistic Krang. Also with how ridiculous the TMNT franchise has become across its various incarnations, the idea of Shredder being an alien is simply no longer as unusual as it once was.

* Vindicated byHistory: While the viewpoint still remains far from universal, the reception to Shredder being an utrom has improved with the passage of time. As the reveal elevated the villain's potential from a human criminal mastermind with an army of ninjas to a cosmic-level threat capable of bringing the universe to its knees. In particular, it's not uncommon to note that Ch'rell is almost an amalgamation of Shredder's skill and strength as a Ninja combined with the intelligence of a much more sadistic Krang. Also with how ridiculous the TMNT franchise has become across its various incarnations, the idea of Shredder being an alien is simply no longer as unusual as it once was.

* VindicatedbyHistory: While the viewpoint still remains far from universal, the reception to Shredder being an utrom has improved with the passage of time. As the reveal elevated the villain's potential from a human criminal mastermind with an army of ninjas to a cosmic-level threat capable of bringing the universe to its knees. In particular, it's not uncommon to note that Ch'rell is almost an amalgamation of Shredder's skill and strength combined with the intelligence of a far more bloodthirsty Krang. Also with how lubricious the TMNT franchise has gone across its various incarnations, the ideas of Shredder being an alien is simply no longer as unusual as it once was.

* DifficultySpike: The 3rd stage in ''Battle Nexus'', Planet Zero, is much more difficult than the earlier stages with tougher enemies and tricky platforming. The game just keeps getting harder from there.

* GameBreaker: The CombinationAttack in the first game. You get it after beating the Ordeal stage with all four turtles. It's activated by a simple push of a button. It's drawback is that can only be used in the Story Mode 3 times in a level but all 3 uses can take a huge chunk of health from every boss. Even [[TrueFinalBoss Oruku Saki]] himself.

* SugarWiki/NoProblemWithLicensedGames: The first and second games (Battle Nexus) based on this series have a cult following, the latter especially thanks to its' challenging enemies, lengthy campaign, lots of replay value, tournament mode, and inclusion of the original arcade game. The third game was not ''quite'' as well received but still has something of a following.

** ''Fast Forward'' has a good vibe to it as well highlighiting the futuristic elements of the series yet keeping a bouncy tone throughout that's quite catchy.
** While ''Back to the Sewers'' loses points in the intro for using clips rather then mostly new animation (likely because of the rushed production of the season). The intro definitely has a in your face feel that feels like a roller coaster ride while proclaiming this incarnation is gonna end in a bang.

** Both the Justice Force and the Ninja Tribunal suffer from this during the attack on April and Casey's wedding. The Ninja Tribunal are demigods said to be the most powerful Ninjutsu masters on the planet, while the Justice Force consists of several {{Captain Ersatz}}es of superheroes like Superman and Green Lantern. Their contribution during this battle consists of being casually swatted aside by the Cyber Shredder and his henchmen.

** Leo ends up becoming BashBrothers with [[ComicBook/UsagiYojimbo Miyamoto Usagi]]. Since then, Creator/MichaelSinterniklaas has been in several other works where [[Anime/FreedomProject his]] [[Manga/{{Phoenix}} character's]] [[Manga/{{Bakuman}} love]] [[Anime/YourName interest]] is voiced by Creator/StephanieSheh, who's well-known for voicing a certain other famous [[Anime/SailorMoon Usagi]].

* WinBackTheCrowd: After ''Film/TeenageMutantNinjaTurtlesIII'' put an end to the initial Turtle mania wave and put the franchise into a DorkAge that went into the later seasons of the 80s cartoon, as well as ''Series/NinjaTurtlesTheNextMutation'' not helping at all, this show managed to prove that the franchise had staying power beyond its initial popularity.

* MemeticMolester: The alien frog from ''Recap/TeenageMutantNinjaTurtles2003S6E12BadBlood''. From his tone of voice and the way he grabbed Cody makes him seen more like a child predator.

* InkStainAdaptation: Karai's characterization in the comic was very different than how she was portrayed in this series, but the latter got so popular this is usually what fans think about when the name of the character comes to mind, and all the other adaptations where she appears took from it in a way. The popular public perception of Karai as a young ninja girl being related to the Shredder with varying degrees of UndyingLoyalty towards him began with this show. And while she didn't get romantic with Leonardo, the seeds of them playing the DatingCatwoman game still got planted here as Leo and Karai did go back and forth several times in the platonic sense on just how redeemable she really was, which would only fully bloom during a later series like the 2012 show.

* AntiClimaxBoss: [[TrueFinalBoss Oroku Saki]]. He's only fought after you beat Shredder with all four turtles and is suppose to be the toughest challenge. Unfortunately you've already gotten the CombinationAttack allowing you to damage him for a good amount of health with three button uses. So it's only a matter of wittling away the rest.

* FanPreferredCutContent: While ''Fast Forward'' is considered to be a divisive series, many would have preferred a second season to it compared to ''[[SeasonalRot Back To The Sewers]]'' as it would've featured Ch'rell taking over the body of a dead Triceraton soldier which could have brought ''Fast Forward'' to be similar in tone to the earlier seasons.