Based on the 1985 OVA series, about which Wikipedia has this to say:
Megazone 23 is an anime series about a future recreation of Tokyo where the citizens are unaware that they live in fabricated reality. It is widely considered a classic of the mecha genre of anime, and it holds a place in history as one of the first profitable Original Animated Video productions.
http://www.compileheart.com/megazone/23.html
http://www.famitsu.com/game/coming/2007 ... 6,0,0.html
http://www.gpara.com/comingsoon/megazone23/20070816/
Famitsu lists the genre as "Adventure/Anime - Robot" and Gpara as "SF Commando Battle Adventure". Go figure.
Comes out on September 13th, and there will be a limited edition as well.