I can't address the movie as a fan of the animated series because I hated the animated series with a passion. Note the past-tense. I had a friend in high school who tried over and over to interest me in Aeon Flux. Watching anything with him meant hearing running commentary. Everything was "bitchin'" or "wicked-awesome" and there were no surprises because anything cool was always preceded by "woah! Shh! Watch this part, this is awesome!" Not sure why he felt the need to "shh" himself. I forgot Aeon Flux more or less on purpose, and we didn't have cable so I had no other exposure to it for years. A couple of years ago I saw an episode somebody had on tape. My reaction was positive, but it was only a single episode. I went into the movie basically unfamiliar with the character and the overall story. Maybe this is the right way to do it, since the Internet tells me that all of the major characters have been simplified for the movie. I'd rather go from a dumbed-down movie to the much-better TV series than vice versa.
So what's Aeon Flux about? In 2011, a virus wipes out 99% of the population. A scientist named Trevor Goodchild manages to find a cure and moves the population to an idyllic, walled city called Bregna. The Goodchild dynasty reigns for 400 years, and for some reason nobody questions the fact that Trevor Goodchild and his brother Oren have reigned over the city for all this time. What they do question is the fact that people are disappearing. Aeon Flux is an operative in the underground movement which is working to bring down the Goodchild dynasty, and when her sister is killed by police, her mission becomes revenge.
That's all I'm going to discuss of the plot, which is too bad because up to this point it sounds like typical, mindless action movie fodder. Aeon Flux is, surprisingly, better than that, and discussing the plot further would reveal its best convolutions. The Seventh Seal it ain't, but Aeon Flux actually has ideas and a pretty good story, and I enjoyed it very much. It's not going to make you think much, but it's not going to hurt your brain, either. The one example I remember of glaringly bad science was equally perplexing to the characters in the movie.
Charlize Theron doesn't normally do anything for me, but after her play the lead in this movie I'm thinking the problem might be the roles I've seen her in (and admittedly, after Two Days in the Valley and Devil's Advocate, I actually avoided seeing Charlize Theron movies). Thanks to this movie, I think I'm going to check out her Oscar-winning performance in Monster, which probably sounds foolish to anybody who knows just how different Aeon Flux and Monster are. No, I know what I'm getting into, and I know what kind of movie Monster is. As far as the rest of the casting goes, I have no complaints. I have seen all of the major actors in movies better and worse than this one. The dialogue is so full of portent that it has to be delivered in an overdramatic fashion to work. Anybody can be overdramatic, so the casting in Aeon Flux is more about visual style than acting talent.
As far as presentation goes, Aeon Flux is well-paced and visually slick. Director Karyn Kusama's only other film (according to IMDB) is Girlfight, which I haven't seen. Clearly she knows what she's doing, is comfortable directing action, and is good at it. There are few visual parallels to The Fifth Element, but for some reason Aeon Flux reminds me of a less-populous, more enlightened and (above all) cleaner version of the same future. It's really too bad Aeon Flux came out when it did because had the release been timed differently, it might have been much more successful. It's very much a popcorn movie, but it's pretty and smarter than one might expect. The professional critics are divided and fans of the original MTV series are mostly disgusted with the changes, but this is a movie people are going to rediscover on DVD.