It's also the last and if this is where the series was headed, I'm glad for that.
I sort of saw this coming, though.
The original series was 22 episodes, an unusual, but not unprecedented number for a TV anime, but when the series's second season was only 11 episodes--a bizarre number of episodes but exactly half the episodes of season 1, which contained two separate story arcs--I went, "crap, they probably got word the project was being scaled back once they were already deep into production." When they announced immediately after season two ended that a theatrical film was in the works, and that it would close out the series, I figured they would simply compress whatever the second storyline from season two was supposed to be into a standalone film.
Well, I can't prove I'm right but I have little doubt about it.
The film is... eh, rushed, compressed and shallow compared to the TV series. The series tackled some pretty weighty issues revolving around free will vs safety in a dangerous world, the role technology plays in society--especially its dehumanizing potential--and the role of the state as protector vs controller, among others. The film is basically a lot of shooting and explosions. If not for a few references to events and characters from the TV series, you wouldn't know it was connected to anything else. In fact, they could have changed some key characters' names and called it an original film with few the wiser.
Additionally, there are numerous spots in the film that seem as if the scenes were adapted from a much more involved plot, presumably from the TV series scripts. Many of these seem oddly truncated or don't contribute to the film's plot, as if they were meant to set up subplots that don't appear in the film. There are also characters introduced in the film that seem like they didn't get the development originally intended.
For example Yao, the personal assistant assigned to Akane (the film's protagonist), is introduced in a far more extended, grander manner than her screen time warrants. It seemed like she'd be at least a somewhat important character - and then she's absent for nearly the entire remainder of the film, only to show back up and betray Akane. I'm sure it was meant to be shocking, but it not only wasn't shocking, it fell entirely flat. We don't know the character. We have no reason to trust her, so her betrayal isn't the least bit shocking. In fact, it seemed like rather clumsy storytelling at that point.
Beyond that, for a film that is supposed to end a TV series, it failed. No one's storylines from the TV series were completed, no one had any revelations. In fact, some characters' fates seem even more ambiguous now. The fact that only two of the series's main characters (out of seven or eight important ones) even figured into the film in a meaningful way just left me feeling cheated. And the ending? A message that pops up on the screen and says, "The world will continue to evolve"? What kinda platitudinous crap is that? No kidding, it'll change, but what about the characters you've left hanging?
Tl;dr version - great TV series, failed film.