Mostly aimed at .hack fans with enough content to sorta water your appetite but not enough to satisfy you in many respects. It's only 3 half-hour episodes in length and wraps things up fairly well (not many obvious plot holes for a short story).
General summary:

Ah yes, and the ending theme is appropriate.

Numbers aren't enough to specify the content, so let me go into detail.
Violence: The story is told in an MMORPG, so while there can be alot of violence, none of it has blood. The violence is central to the plot, and though no one is shown to actually stab or even harm someone else, it's implied that such things are going on.

Nudity: Nothing even close to sex or references. There are moments of somewhat vague (but not blurred) nudity, and a prolonged scene where it's obvious. Also, the avatars of characters aren't entirely modest.

There is no magic in this show. As in all .hack films, everything characters do is possible in the RPG. However, the .hack franchise has an odd point of view with respect to human consciousness. Also, the "world" itself has its own stories with respect to religion for in-game experience, though this isn't important or mentioned in this show.