How have I not heard of this?

Gaiman summarizes:

Avalon is a remarkable film -- it looks astonishing, is haunting, deep, frustrating and magical in equal measure, like an art-film version of the Matrix, or a middle-European Philip K Dick structure created by a Japanese director more to unsettle you then to excite you. In a grey, futuristic world, people enter a consensual reality run by computers to play illegal war-games, and the finest player is a woman called Ash. There are hidden levels to the game, and to reality. It doesn't look like anything else: it's like an SF tone poem, or a mood, as much as it is a story.

Coming out December 9th, along with a zillion other things I want. :P