I suppose an average score is sufficient for this movie. The story was not bad...it wasn't great, but it was good enough to hold my interest. However it gets a little complex at times; basically, just try to remember that Olympus is a separate city from the rest of the Earth, the latter being ravaged by global war and chaos. As the human race kills itself elsewhere, Olympus survives because of a coexistence with a kind of modified human race called Bioroids, who are like humans only with subdued emotions and renewable life cycles. Meanwhile a computer system named Gaia was designed to monitor both humans and Bioroids, and make decisions for the city based on what is best for both races.
Then you have to remember that the "Appleseed" and the "D-Tank" are the two crucial items for the fate of the city. What each of them does, specifically, is a detail I won't describe here, both because I don't want to spoil anything, and also because I'm not entirely sure I know myself. Then you need to distinguish between the ES.W.A.T., which seems to be some kind of third-party force, the O.R.A., which is the Olympus Regular Army and which is composed entirely of malintentioned humans, the Elders who supposedly interact with Gaia, and a woman named Athena who is apparently the Prime Minister of Olympus, although I didn't even know that until I read it in an online description.
If that's not enough, you'll have to distinguish between the robot soldiers, the android soldiers, the partially robotic cyborg soldiers, and the human soldiers wearing robot armor...and of course the human soldiers in regular clothes, and the Bioroid soldiers in regular clothes. But once you've got that down, you should be ready to go.
Anyway I'll admit that it wasn't as bad as I make it sound...somehow I managed to at least know the gist of what was going on. Also, if "hardcore" scores points with you, you may want to check this out, because there are some pretty cool battle scenes. However, the creators took a big risk by animating this the way they did: that is, using flat-shaded 3D animation. Animators have long sought to achieve the style of 2D with the fluidity and freedom of 3D, but this technique of flat-shading was, in 2004 (and still today), in its infancy, and it shows. The characters in Appleseed will have brief moments of beauty, but spend the rest of the film looking like plastic dolls with terrible lip-synching. The music was pretty bad too, in my humble opinion.
In conclusion I'd say this one is for animation buffs only, simply because there aren't too many films made in this kind of 3D-anime style, and it almost manages to pull it off (although ultimately it fails). Also, like I said, it might be worth it if you get a special kick out of robot fight scenes. But all things considered, I'd say "Appleseed" is nothing special.