Ok. I am a HUGE fan of the show, as some of you may know. This movie... well... yeah it was awful. I would have rather watched the Ember Island Players. I'm going to pick apart this movie by character and episode to tell you what they got wrong. This also has spoilers btw, so stop reading if you haven't seen it.
Aang:
Or should I say Ahng? They pronounced his fucking name wrong. They said ah-ng not eh-ng (eh like a Canadian). They also said ah-vah-tar. This annoyed me throughout the movie. Katara and Sokka found him under some ice, not in an iceberg. His arrow had really weird markings on it. He was WAY too serious. Really, I don't remember her smiling. Aang is 12. He needs to have more fun.
Appa:
Not much wrong there. He could have been in it more, but I'm not complaining.
Azula:
She was just shown at the end. Makes sense, that's how Book 1 ends anyways.
Iroh:
Or should I say Eroh? They pronounced his name wrong too. Iroh needed to be fatter, happier, and wiser. In the series, he's the jolly tea drinking with the wisdom of a lion turtle. Here... I don't know. He was just plain. It was weird.
Katara:
Not much here. She didn't really have hair loopies though >:[
Momo:
They didn't even call him Momo, and he was in about 30 seconds of the movie.
Sokka:
Or should I say Sohka. Again, name fail. They called him soh-ka not saw-ka. And he wasn't funny! He was way too level headed. No jokes. srs character r srs.
Zuko:
This one was weird. I didn't even realize the little mark on his face was his scar till I saw it a couple times. He also wasn't angry enough. Season 1 Zuko was very angry. And he wasn't in it enough. Aang and Zuko saw each other about 3 times...
Monk Gyatso:
He was black... what is this i dont even... Yeah, you never hear him talk, as he's just in a few flashbacks.
King Bumi:
He wasn't even in it. They never went to Omashu.
Jet and the Freedom Fighters:
They weren't in it. Not at all. How they'll make Book 2, I'll never know
Haru:
He was in it for some reason, but they never called him Haru. Also, he was on what was supposed to be Kyoshi's Island (I'll get to that later)
Suki and the Kyoshi Warriors:
They weren't in it. At all. Suki is a major part of Team Avatar. I don't know how they'll manage to make book 3 without her.
The Mechanist and his son:
Not in it. I'll get to the Northern Air Temple later
Jeong Jeong:
Not in it. I can kinda understand that. That episode was mostly a filer, and he only comes back at the end with The Order of the White Lotus
Ozai:
He had too big of a role. You don't even see his face until Book 3 Chapter 1, but in the movie, he's walkin all around and talkin.
Roku:
Not in it. What the hell, guys? Aang never talked to him in the spirit world. I was disappointing.
Zhao:
Not much wrong here. He needed bigger side-burns and a much larger voice. He was also never promoted to Admiral.
Koh the Facestealer:
Not in it, but Aang does go talk to a dragon in the cave Koh is supposed to be in.
La and Tui: Kinda in it... Tui is killed by a knife, not fire. And Aang and La never become the big monster thing to fight off the Fire Nation Ships
Arnook and Pakku:
Kinda in it... but they were like, the same person. The same person who trained Katara and Aang was the chief. And neither were called by their names.
Bato and Hakoda:
Not in it, but Hakoda is mentioned a couple times but Sokka as just "dad".
Hahn:
Not in it, surprisingly, seeing that half of the movie was at the Northern Water Tribe. So there was no conflict between him and Sokka.
Kanna aka Gran Gran
She was never called by any of those names. They called her "grandmother", which annoyed me greatly.
Princess Yue:
Nothing really, but she wasn't engaged to Hahn as he wasn't in it.
Now I'll go by episode
The Boy in the Iceberg and The Avatar Returns:
2 part episode, and the beginning to the movie. The way they found Aang was wrong. Gran Gran isn't named Gran Gran. Fire Nation uniforms are weird. Fire Nation soldiers run weird. Zuko and Iroh were weird. The way they found out Aang was the avatar was weird. These whole scene(s) was(were) weird.
The Southern Air Temple:
When they get there, there wasn't snow. wtf? The Southern Air Temple is cold, dude. They never named Momo, just kinda found him for 5 seconds. They never saw the statues, and the non-existent statues never lit up when Aang went into the Avatar State, which told the world that "the Avatar had returned".
The Warriors of Kyoshi:
Kinda didn't exist. There was a Kyoshi Island... kinda. There was a village, captured by the Fire Nation, and it had a statue of Kyoshi. I... guess it was Kyoshi Island? What is this i dont even...
The King of Omashu:
Didn't exist. They never went to Omashu. They never met King Bumi. Sadface
Imprisoned:
Again, kinda existed. Haru was there... on Kyoshi Island. And he was never called by his name. And there wasn't a giant metal boat.
Winter Solstice Part 1: The Spirit World and Winter Solstice Part 2: Avatar Roku:
Didn't exist. Aang didn't meet the panda thing. Aang never traveled to that temple on the solstice. Aang never spoke to Roku. Roku never told Aang about the comet.
The Waterbending Scroll:
Kinda existed. Katara got the scroll... on what was supposed to be Kyoshi Island (I guess they tried to mix a bunch of episodes for time purposes). There were never pirates.
Jet:
Didn't exist. They never met Jet and the Freedom Fighters. They never did that cool thing with the geysers.
The Great Divide:
Didn't exist. I understand, fuckin filler episode.
The Storm:
Didn't exist. Back-story episodes aren't needed in a remake movie.
The Blue Spirit:
I think this is better explained in the description for The Nortern Air Temple (trust me)
The Fortuneteller:
Didn't exist. More filler episodes
Bato of the Water Tribe:
Didn't exist. They never met Bato. They never went Ice/Rock Dodging
The Deserter:
Didn't exist. Poor Jeong Jeong
The Northern Air Temple:
Here starts the second half of the movie. Aagn travels alone to the Northern Air Temple and is trapped by Zhao (wut?). Then the Blue Spirit comes in and saves him (wut?). And the Mechanist wasn't there (WHAT?!?!). Like... wtf? The Blue Spirit, as you can see, is a few episodes before The Northern Air Temple.
The Waterbending Master:
Not much for this. Team Avatar arrive at The Northern Water Tribe. Sokka meets Yue. Pretty much it.
The Siege of the North, Part 1 and 2:
Most of the movie is here. Zhao's army invades. Iroh follows him to the Ocean and Moon spirits (seems normal, right?). Then Zhao knives the SHIRT out of the fish (Zhao pwns n00bz). Iroh scares him off. Yue floats on her back. The white falls out of her hair, and floats into the dead knived fish. Meanwhile, Aang is just standing in the battle, watching, then all of a sudden, he's in the Avatar State, and bending the SHIRT out of the water. He just bends a big wave and the boats turn around. I was hoping I would get to see a giant Aang/Koh monster in live action
That's about it. Compared to the TV series, I give a 3/10. By itself, about a 6/10