I'm interested in learning. So, what makes this the definitive take? Does this show borrow or use actual storylines from the comics? Examples? Are there many changes made from the source and if so, are those changes better/worse or no different? Examples?
For most comic book fans, there is no comparison. More than the live-action movies, more than the 1960s TV series, more even than the original comic books, Batman: The Animated Series was and remains the definitive presentation of Batman or any superhero in an animated medium. Taking bits and pieces from the best that had come beforehand, Bruce Timm and Co ushered in a whole new era of childrens’ animation and created frankly one of the finest television programs ever aired. It borrows from many iconic and brilliant Batman storylines like The Laughing Fish, The Crime Doctor, The Joker's Five Way Revenge, No Hope in Crime Alley, The Demon's Quest to name a few.
The voice acting is beyond compare. For many (including myself), when they read the comic books, the voices they hear for the good guys are Kevin Conroy (Bruce Wayne/Batman), Efrem Zimbalist Jr (Alfred), and Bob Hastings (Jim Gordon). Conroy knew how to differentiate his voice as Batman. And Loren Lester even managed to make Robin/Nightwing sound cool. And let’s not forget that the show invented the long-running character of Renee Montoya.
As for the villains, more than enough has been written about Mark Hamill’s incredible work as The Joker, as well as Arleen Sorkin as Harley Quinn (who was later ret-conned into the Batman comic book world just like Renee Montoya). But let’s take a moment to remember Michael Ansara’s cold-bloodedly monotone Mr. Freeze (who also helped re-invent the comic book character as a serious villain), Paul Williams' aristocratic and menacing Penguin, Adrienne Barbeau's sensual and seductive Catwoman, David Warner’s deliciously arrogant Ra’s Al Ghul, John Glover’s deadly serious Riddler, and Richard Moll’s terrifically likable and sympathetic Harvey Dent and his cruel, conflicted Two-Face. Special mention must be made of Roddy McDowall. His stunningly touching and operatically emotional Jervis Tech was a highlight, especially in a powerful moment later in the series where The Mad Hatter explains just what lengths he would go to to get Batman out of his life.
Tonally, the show seemed to put itself mainly in a 1970s Dark Knight Detective template, but also tossing in bits from the Tim Burton movies, the 60s TV show, the Dick Sprang/Bill Finger 1940s stories, and the darker late 1980s comic books. Like those Dennis O’Neil/Neal Adams stories, Batman was a dark and brooding adventurer, and a whip-smart detective. But he was not obsessive and not a psychopathic jerk incapable of having formed relationships. And Bruce Wayne was just foppish and playboy-ish enough to get giggles from his fellow socialites, but he never went so far as to render Bruce Wayne impotent in the business world and useless as a force for good. Conroy’s Bruce Wayne was a publicly respected figure and a genuine philanthropist. The villains were menacing and (within the limits of BS&P) murderous, but their violence was never so grotesque as to render Batman’s efforts futile. There was plenty of action and adventure, but never at the expense of story and character.
The groundbreaking designs were straight out of 1940s art deco, taking a bit of inspiration from the 1940s Fleischer Superman cartoons but with a twist. In order to capture the darkness and shadowy mood of Gotham City, the artists actually worked from a black canvas, adding color to the already existing blackness. The Gotham City of this show is a timeless one, with black and white TVs and tommy guns mixed with computers and cell phones.
The stories are timeless too. In fact, that is the key to the show’s lasting success. Take away the artwork, the acting, the music, the violence, action, and suspense, and you still have something has yet to be replicated in American childrens’ animation. I’m talking about the scale of the storytelling. It was rarely epic and it was rarely larger than life. The storytelling was exactly to scale of human experience.
While there were plenty of escapades involving battles with Batman and his gallery of rogues, as well as gritty crime stories involving the less flamboyant outlaws, many of the episodes stepped back and took a look at the regular people living in Gotham. Some of the very best episodes involved the smallest of stories involving these always three-dimensional characters.
A typecast actor, struggling to survive after a role in superhero show has rendered him unemployable (Beware The Grey Ghost). A divorced ex-convict, willing to go to dangerous lengths to see his daughter (See No Evil). A mob moss deciding whether to turn state’s evidence after his son gets hooked on drugs (Never Too Late). A disgraced doctor, forced to kidnap a colleague to assist in life-saving surgery on his crime-boss brother (Paging The Crime Doctor). A veteran cop coming to terms with his loneliness and emptiness as someone from his past marks him for murder (A Bullet For Bullock). The Gotham City of Batman: The Animated Series was a real city, filled with real people living lives not unlike you and I. But in this city, that guy who you cussed out after he cut you off on the Freeway — he might just be The Joker (Joker’s Favor).
Nearly 23 years later (dear God), the show still holds up as an intelligent, exciting, tragic, funny, and moving action drama. It is the highest quality adult entertainment, that just happens to be pitched at a level that still renders it appropriate for children. It is easily one of the finest cartoons ever made, and perhaps the very best adaptation of a comic book in any medium.
It had a loose continuity with several of it's villains, such as Clayface, Mr. Freeze, Man Bat, The Clock King, and the on going relationship between Batman and Catwoman. One of the reasons why the show is so easy to watch is that you can slot in any episode and watch it without worrying having missed the previous episode or episodes, unless it's a 2 parter.
To answer your question about improvements, I'd say Mr. Freeze is a no brainer. He was a gimmicky shallow villain in the comics until BTAS turned him into a deep tragic character with a whole new back story involving his sick wife. Harley Quinn is another gift from this show. So is Renee Montoya.