Based on the movie version of the animated series, "Aeon Flux" for the PS2 is a representation of the futuristic setting presented in that series. It uses the series' trademarks of acrobatic martial arts and gunplay to decent effect.
The main character is the titular "Aeon Flux", a rebel against the high-powered corporate government of the future. Using her wide variety of skills, she undergoes missions against the corrupt government. For the most part, the game follows the movie's plot, and I can't discuss it without spoiling the movie. There are several divergent points attempting to explain the difference between the TV series and the movie, as well.
The gameplay is the strongest point in this game. The wide variety of acrobatics and fighting moves available mean that it is fairly enjoyable even later into the game. A combination of shooting and melee is required, and the integration of the two elements is done reasonably well. Aeon Flux can kick, punch, shoot, dive, and leap off of walls, all with reasonably decent coordination. However, there is not much that really stands out as being different from Aeon Flux's many rivals in the field of acrobatic fighting games.
Graphically, this game doesn't stand out. While it isn't bad, there's not much to really make it "good" either. Character models seem detailed, but tend to move "inhumanly" - too jerky and too much. The audio is similarly mediocre, with the futuristic/techno sounds expected of the cyberpunk genre.
All in all, there's not really a good reason to recommend this game. Fans of the film who really want to play a version of it might be interested, but overall it is the same as many others of its genre.