One of the good things about sci-fi, generally speaking, is that they are set in some unknown time and place that is not linked to the time and place they are actually being created in. This should prevent them, in theory at least, from becoming dated in a few years. Unfortunately, this isn't always the case. The prevalent style of film-making, music, fashion etc tend to have an influence even when the creators try to imagine what the future might look like.
Appleseed suffers badly from this problem. While it is set in some far distant future, it plays like a 80s b-movie thriller, right down to the cheesy background score. Thankfully, it is short (about 65 mins), so there are no gratuitous action sequences and story keeps humming along at a brisk pace (even if the story is rather weak, in the tradition of mediocre movies of every era, not just the 80s). There was a chance to do something interesting, but the film-makers have clearly missed the opportunity.