Most of this animated movie is based on the graphic novel of the same name, which was published way back in 1988. I've read it several times, so I was familiar with the story and characters going into the movie. Which was confusing at first, because the beginning of the movie doesn't seem much like the graphic novel at all.
The first half-hour or so of the movie isn't in the graphic novel. It's mostly about Batgirl aka Barbara Gordon, daughter of Commissioner Jim Gordon. Unlike the source material, this version is in love with Batman. At first it's unrequited, but eventually they consummate the relationship. After that, she loses perspective. She eventually gives up being Batgirl after realizing that she's unable to be objective when Batman is in danger.
After that, the movie follows the graphic novel very closely. The Joker enters the story, having recently escaped from Arkham Asylum. We see some flashbacks to the events that caused a normal man to become the Joker...at least, one possible version, as he says himself that he prefers the past to be multiple choice. The rest of the story is about the terrible things he does while free, and how it impacts the Gordons and Batman. If you've read the graphic novel then you already know what happens, and if not, I won't spoil it.
The parts of this movie that were from the graphic novel were great. The visuals are well-drawn. Kevin Conroy is the best Batman voice actor hands-down, and same for Mark Hamill with the Joker. The story follows closely with the source material, and if you ignore that first half-hour, it hangs together nicely. And I know I'm not in the majority here, but I actually like the ending...it feels somewhat abrupt, but I think it fits together with Batman's stated desire from earlier in the story to understand the Joker on a non-violent level.
Unfortunately, that the first half-hour doesn't fit in with the rest of the movie at all. Showing that Barbara used to be Batgirl, that's necessary and could have been done in about five minutes. Instead, the movie adds a subplot with a random criminal trying to seduce Batgirl, with no Joker involved at all...who is supposed to be the primary villain.
Then there's the bizarre sexual relationship between Batman and Batgirl. Batman shows no signs of being attached to her as anything beyond a work partner, so why would he sleep with her in the first place? A normal man, sure, but this is supposed to be the always-self-controlled superhero who won't let anything interfere with his mission. If sex was necessary for some reason, why not add Robin, who is Batgirl's love interest in the comics and would make much more sense? The writers were clearly trying to come up with a reason for her to quit being Batgirl, but it falls completely flat and doesn't mesh with the graphic novel story.
By the end of Batman: The Killing Joke, I was happy to have watched it, since the last hour is a well executed adaptation of the graphic novel. I just wish they hadn't bothered with that first bit.
