A piece of fan art of Avatar: The Last Airbender
Avatar: The Last Airbender received critical acclaim. Max Nicholson of IGN called it a "must-watch" and described it as "one of the greatest animated series of all time". Nick Hartel of DVD Talk called the series a remarkable, "child friendly show" whose legacy "should endure for years to come". Erik Amaya of Bleeding Cool described the series as "impressive in its sophistication" and "fantastic". Henry Glasheen of SLUG Magazine called the series "adventurous and exciting", a "classic" and occasionally moving. According to Brittany Lovely of Hypable, it tells "complex and beautiful" stories. Joe Corey of Inside Pulse described the series as an anime-action hybrid.[64] Chris Mitchell of Popzara called it one of best shows to air on Nickelodeon, praising the series' background music and voice acting. D. F. Smith of IGN recommended it to viewers who enjoy action-adventure cartoons.
Rob Keyes of Screen Rant called the series "one of the greatest cartoons ever made". Mike Noyes of Inside Pulse recommended it to viewers who enjoy "great" adventure. Gord Lacey of TVShowsonDVD.com called the series "one of the finest animated shows ever". According to Todd Douglass, Jr. of DVD Talk, adults will enjoy the series as much as children do. Joshua Miller of CHUD.com called it "phenomenal" and "one of the most well animated programs (children's or adult) American TV has ever had"; according to Miller, the series is heavily influenced by anime. Tim Janson of Cinefantastique described it as "one of the most engaging animated shows produced". Dennis Amith of J!ENT called the series "one of the best animated TV series shown in the US by American creators". Amith praised its sophisticated storylines, edginess, humor, and action. Franco "Cricket" Te of Nerd Society described Avatar: The Last Airbender as "one of the best cartoon[s]" he had ever seen, recommending the series for its characters and plot. Scott Thill of Wired called the series engaging and its setting, influenced by the Eastern world, "fantastic". Kirk Hamilton of Kotaku said the series should be part of the golden age of television, and recommended "the sophisticated kids show" to others.
The show's writing and theme have been widely praised by critics. Michael S. Mammano of Den of Geek called the plot "smartly-written" and praised the animation. Nicole Clark, writing for Vice News, wrote that the show's narrative depth was "its greatest asset", and praised the story's "emotional authenticity" and how it "expose very young viewers to darker subject matter, like genocide and authoritarianism, while giving them a framework for understanding these issues." Jenifer Rosenberg of ComicMix liked the program's emphasis on family, friends, community, and education. According to Nick Hartel, the series touches on themes of "genocide and self-doubt" without frightening younger children; rogue characters are redeemable, sending an important message that people can change and are not bonded to "destiny". Chris Mitchell called the plot "fantastic". D. F. Smith compared the series' plot to Japanese action cartoons, calling its tone and dialogue "very American" and praising the humor leavening an epic, dramatic theme suitable for all ages. Rob Keyes also praised the series' humor and affecting plot: "[It] will capture your hearts".
According to Mike Noyes, the series amalgamates elements of "classic fantasy epics". Todd Douglass, Jr. called the plot engaging, well-thought-out, and meaningful. The series' concept is "well-realized", with a consistent story. Douglass wrote that the characters "[have] a real sense of progression", and praised the writers for their humor, drama, and emotion. Joshua Miller called the series surprisingly dark despite its "silly" theme; the plot is livelier than that of Lost and, similar to the latter show, emphasizes character development. According to Miller, its writing was "true adult levels of storytelling". Tim Janson described the series as more than fantasy-and superhero-themed, seeing the characters as central and relateable. "Cricket" Te praised the series' use of Buddhist philosophies and the diverse presentation of its themes of courage and life. Kirk Hamiltion praises the series for expressing towards its audience to be themselves and for its quiet progressivism.
Critics also praised Avatar: The Last Airbender's character development, art, animation, and choreography; Eric Amaya enjoyed the expressive animation that complements the writing. According to Amaya, the elements were influenced by Hayao Miyazaki. Todd Douglass, Jr. called the character development interesting,= while Nicole Clark wrote that the show "managed to do what so few shows even today have: assemble a cast of characters that depicts the world as it is, with a range of identities and experiences." Jenifer Rosenburg praised the series' portrayal of females as "strong, responsible, [and] intelligent". According to Joshua Miller, the bender characters' use of bending for everyday activities brings "depth and believability" to the avatar world. Miller called the series' designs "rich and immersive", with each nation having its own, detailed look. He praised the action scenes as "well rendered", comparing the development of the avatar world to that of The Lord of the Rings, and the fight choreography as "wonderful in its most minor details". D. F. Smith enjoyed the series' painstaking backgrounds. "Cricket" Te praised each episode's color palette and the choreography's combination of martial arts and magic. Nick Hartel criticized the animation, although he found it an improvement over previous Nickelodeon shows. Chris Mitchell called the animation fluid. "Cricket" Te agreed, noting its manga influence. According to Brittany Lovely, non-bender characters in battle are "overshadowed" by their bender counterparts. Joe Corey called the animation's action and environments a "great achievement", and Rob Keyes praised the series' fight choreography. According to Kirk Hamilton, the action sequences in the series are amazing while being child-appropriate and exciting.