These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Angst? What Angst?: Bradford likes his mutation into Rahzar despite it being much more horrific looking than his Dog Pound mutation, since it allowed him to regain some of his ninja speed.
Anvilicious: The moral about not letting insults get to you, to the point where Raph is blatantly portrayed as putting his "insult ignoring training" to "good use".
Awesome Art: The show is one of Nick's better animated CGI cartoons. The acute eye will notice subtle "blink and you'll miss it" moments about the body language of the characters and facial expressions that really help set the mood for certain scenes. The occasional 2D elements that get thrown in every so often make the show visually fun to look at.
Then there's the fight scenes. They flow well, feel realistic, and can be both fun and exciting to watch. One of the best examples would be Splinter and Shredder's fight at the end if season one.
Base Breaker: Either Michelangelo is funnier than ever, or he's more annoying than ever.
Casey Jones, even before he appeared in the show!
Donatello. You either think his crush on April is cute or Squick.
April's being angry with the Turtles after they accidentally mutated her dad has caused either people to turn against her or explain why she's justified in acting that way.
People either love the new personalities for the Turtles, or think it's crap.
Broadly speaking, their personalities still line up with both previous shows' theme songs. The biggest change is Donatello having a crush on young teen April (and Raphael is somewhere between the 1987 and 2003 shows on the anger scale).
The quality of this version of the turtles is arguably the most divided when it comes to the fans reactions of the whole franchise.
The reworked designs of the Turtles seem to be something of a point of contention among a few fans.
Fans are also divided over whether or not it is a good thing that Spike became Slash.
Splinter+The empty broken mutagen canister Mikey called "mom."
Leo+Karai's throwing knife.
Continuity Lock-Out: Not even a season in, and already there might be a serious case of continuity lock-out ahoy. Episodes build on each other, there are no "previously on" segments except for the opener, and sometimes things aren't explained as well as they could be for viewers who might have missed an episode. Then again, for the fortunate ones who have internet, Nick.com is kind enough to leave some episodes up for a few weeks in case you missed them.
Crack Ship: Donatello/April shippers and Casey/April shippers have been at each other's throats since the first episode. Those who have been annoyed by their behavior have started shipping Casey/Donatello to troll them for their irrational behavior.
Die for Our Ship: Casey Jones has been hit with this by many April/Donatello shippers.
This reaches into Fandumb territory as some April/Donnie shippers have declared the show of loosing “quality" (which is untrue as season 2 has had some brilliant story telling and animation thus far) and have declared they will not watch it anymore... simply for the ship teasing of the (almost always canon) Casey/April ship.
Ear Worm: The theme song; seems to be a tradition in the TMNT franchise.
In "New Friend, Old Enemy", Splinter teaches Leonardo that victory is more important than fairness. Granted, he's talking about fighting (potentially) to the death, but perhaps they should have clarified that to the kids watching.
Fountain of Memes: Suprisingly enough this version of Raphael has been the source of most of the show's memes.
Genius Bonus/Fridge Brilliance: In Episode 13, the Rat King wears an outfit nearly identical to the ones worn by medieval Plague doctors (long black coat and black wide-brimmed hat). The Bubonic plague was spread (partly) because of fleas being carried by rats.
Growing the Beard: The tone of the show became more focused and consistent mid-first season, starting with "The Gauntlet", the arcs that were previously only hinted at or set up became more prominent, and mostly dropped the Monster of the Week format. Later in Season 1, Karai's introduction upshot an interesting dynamic with Leonardo, some new and interesting setpieces were introduced, and the fight scenes and animation becoming far more consistent and fluid. Season 2 seems to be helping it along as well, due to heading into a somewhat darker direction.
Harsher in Hindsight: At the beginning of Rise of the Turtles Part 2, Mikey wants to drink some mutagen, but Don points out that it may turn him into a pile of goo. Fast forward to The Pulverizer Returns....
Also fast forward to Mikey Gets Shellacne where we see what happens when Mikey does use more mutagen on himself.
Hilarious in Hindsight: Donatello/April and Leonardo/Karai were both ships that only received mere teasing in the 2003 series rather than anything serious. This series takes those teases and makes them officially acknowledged in-universe.
Donatello and Casey's friendly rivalry and name calling in the 1990 film, all of a sudden becomes a lot funnier now that the two have received Die for Our Ship between those who pair them with April in this series.
Ho Yay: Mikey and Leatherhead in "It Came From The Depths".
Jerkass Woobie: Raph in Cockroach Terminator. Raph shows that he's clearly afraid of regular cockroaches, but then he has to put up with a mutant cockroach and the other turtles are absolutely no help since they either make fun of him or don't give him any sympathy.
Happens to him again in season 2 when Spike becomes Slash, hurts his brothers, and has to fight him. The ending where Raph is looking at a chewed up leaf really sends the message that his best friend is gone and has turned into a monster.
As of the season finale, Karai now qualifies, as she is actually Splinter's daughter and has been lied to her whole life by Shredder, and she still thinks that Splinter's the one who killed her mother and wants vengeance.
The term "sadorable" has become extremely popular on Deviantart.
A certain preview for the two part finale for season one shows the turtles and April having a little dance party. All three dances shown has become a bit memetic. So you know it shows Leo shuffling. Donnie and April, of all dances they could of done, doing the funky chicken. Then Raph's dance, which might be the most memetic of all.
"[Insert character name here] confirmed for season 2!" (To the point where fans will search for the most obscure characters possible to keep the joke going.) It'll probably die down once season 2 actually comes along though.explanation This originated from the writers announcing that Casey Jones would appear in season two…before season one even aired.
Moral Event Horizon: If Shredder killing Splinter's wife and burning his house down or teaming up with the Kraang isn't bad enough, then there's him kidnapping Splinter's daughter Miwa to raise as his own and naming her Karai (meaning "weapon"), blaming Splinter for murdering her mother, and making Karai hate her biological father.
Spike at first came off as a Well-Intentioned Extremist because Raph was mad at his brothers. However, he crossed it when he not only ignored Raph's pleas to not hurt the other turtles, but went after him too.
Narm: Mikey calling Kirby "Wing Nut" after he's been mutated into a bat and the turtles are trying to trap him. Which is lampshaded by Donnie.
Donnie: You are not giving Mr. O'Neil a monster name!
Nausea Fuel: Mikey's shell acne throughout the whole episode of Mikey Gets Shell Acne.
Although this can be made sinister when they want it to: "The turtles must be eliminated from this place, and all other places."
As horrifying as the Pulverizer's mutation into Mutagen Man is, there's just something hard to take seriously about his high-pitched voice when he screams "It burns!"
Kraang Primes's voice was this for many people. Perhaps inevitable, considering that they were voiced by Roseanne Barr, who is known as a comedian first and the casting choice was considered pretty strange to begin with.
Leonardo tended to get a lot of reactions ranging from apathy to dislike from fans in previous incarnations due to being, what they felt, to be a rather boring character. This incarnation gets a fair amount of like due to the show making an effort to showcase him as still learning to be a leader, as he has just started, and the addition of other characteristics (his love of Space Heroes and disobeying Splinter a bit more frequently).
One can now argue Raph has been rescued from the heap after "Operation:Breakout" as he took several levels of kindness within the episode. A notable example is his behavior towards Mikey in the episode. In the beginning he intentionally does something he knows Mikey can't get enough (albiet at the expense of Donnie), his once an episode Dope Slap came off as a warning for Mikey to mind his manners (Mikey basically just called Leo stupid, which visibly made Leo angry) and near the end he laughs at one of Mikey's jokes while patting his head. It helps that he has similar behavior towards Donnie in the episode. When he finds out that, yes Donnie still has a crush on April he recommends Donnie not involve him, both as something he obviously thought was helpful advice (since he just embarrassed Donnie) and because he was clearly a little angry Donnie was, in a sense, using him. This has unintended consequences as Donnie leaves without the others on a resque mission for April's dad. He obviously felt bad when he realized this and in the end retold the episodes events in a way that made Donnie look like the big hero of the day which resulted in Donnie getting a hug from April. It probably helped even more that he was called out by Leo for his negative behavior and then, as stated above, made up for it by the end of the episode.
Romantic Plot Tumor: Almost every episode featuring April in a big role is going to heavily feature Donatello's obsessive crush on her, and it's gotten to the point where many are tired of it, especially now that Casey Jones is in the picture and making it a love triangle.
The Scrappy: All of the turtles, save for Leo, got into this zone:
Michelangelo gets this from one side of the Broken Base, due to feeling the show downplayed his Hidden Depths in favor of making a bigger deal on his humorous side, which results in him being grating due to him missing the point of usually very high stakes consequences.
The hate seems to be magnified a bit with him constantly whining about the Rat King's name in the latter's debut episode. Aside from the fact that it seems like a Take That to a classic character with an established history and fanbase, Michelangelo seems to think he has dibs on how villains should name themselves and would not shut up about it for the whole episode.
Raphael, due to being a bigger jerk in this series than he's usually depcited, has his fair share of people who dislike him.
Donnie has landed himself in this by the end of season one. His crush on April was viewed by fans a cute and even endearing during early season one, then suddenly it stopped being referenced to for a few episodes, then it came back…but extremely flanderized. More focus starts getting put on it and we get to see Donnie make…less than rational choices because of it. Then there was Operation: Breakout. Raph tells Donnie to leave him out of his attempts at impress April. (Raph clearly didn't like being used like that and was offering some advise he seemed to think was helpful. ) So what does Donnie do? He basically goes on a VERY dangerous rescue mission, by himself, without telling anybody, to get April's dad away from the Kranng. Not only that but he almost gets himself and Mr.O'Neal killed multiple times. All to impress April.
Outside of the turtles are the Kraang, as they get this mostly for the fact that once they start talking, they're almost never going to shut up. As time has gone on, the show seems to have tried to phase out the humor aspects, possibly saving them a little.
The Pulverizer is quite disliked for being an obnoxious fanboy whose levels of stupidity range from uncanny to mind blowing.
Spiderbytez, an intentional case, for being a crude, realistically obnoxious person before his mutation, and only got worse upon it. Does(n't) help that grumpy neighbors like him exist and are one IRL.
Special Effect Failure: While the show's CGI is generally fairly good, sometimes an acute eye will spot that there's something off about the skyline or the distant buildings.
In-Universe, the Turtles reaction to the sea monster guarding the Kraang fortress falling in love with their submarine.
Depending on whether or not you believe the mutagen made the turtles related to Splinter by blood the fact that Karai is infact Splinter's daughter may have very well caused this reaction in some fans. Especially since Leo had/has a crush on her and Raph admitted she's hot "in the evil way".
The people who were guessing that this version of Karai and Splinter are related since before the show even aired (due to promotional material) found the Leo+Karai ship gross, especially if they're in the party that believe the Turtles and Splinter are related thanks to the mutagen. The confirmation that yes, Karai is Splinter's daughter has caused several people to abandon the Leo+Karai ship.
Some fans find any mutant+human shipping to be a bit...odd.
Concept art notes◊ on the Mousers reveal that their "gut" carries 5 Rat Carcasses. Ew.
Shipping: Donnie and April have been getting this since the first episode. Also, people started shipping Leo with Karai as soon as the description for "New Girl in Town" was released (a legacy of the 2003 show).
Casey didn't appear until Season 2, but he got Die for Our Ship from Donnie X April shippers long before his debut.
Stop Helping Me!: The turtle's basic reaction to anything "The Pulverizer"/Timothy does to try and be more like them or be useful to them.
Believe it or not, the most controversial change is the addition of a third toe on the Turtles. Fans exploded.
April being de-aged to a teenager hasn't been taken very well. And as of "Monkey Brains," people are complaining about her "empathic" ability and Splinter's decision to train her in ninjutsu because of it.
Neither has the replacement of "Cowabunga!" with "Booyakasha!"
Though the decision to make her Hamato Yoshi's biological daughter is something that threw fans off. Especially since they saw that plot-twist coming a mile away.
Within this particular version, the second season's Darker and Edgier turn, in which April's father becomes a mutant, and as a result now hates the Turtles for causing it to happen, despite the fact that it was an accident.
While stylized like everything else in the show, the Kraang's disguises are droll businessmen whose eyes and mouths scarcely move, as if the Kraang are barely trying with their disguises, creating a rather odd and creepy effect.
Then there's Mrs. Campbell, who is also a Kraang creation, and only gets creepier during her fight with the turtles.
There's something creepy about the realistic lips that the mutated Pulverizer aka Mutagen Man has.
The Untwist: Many fans saw the first season finale's twist about Splinter's daughter coming a mile away. The fact that Hamato Yoshi never had a daughter in other continuities and that in continuities where she was Shredder's daughter, Karai was always explicitly referred to as his adopted daughter is what made it easy to predict.
What an Idiot: Episode 6. A Kraang takes control of Donnie's robot and the guys futilely attack it, claiming it has to have some sort of weak spot...completely ignoring the Kraang that's just sitting on its head right out there in the open.
The season 2 premiere has the turtles (except for Donnie) playing dodgeball with the Kraang communication orb. Which Donnie calls them out on. Nothing new for Mikey and Raph, but Leo should've known better. Sure nothing bad came of it but still.
A better example would be Mikey telling April that it was their fault that her father became mutated, causing her to hate them