It appears to be pretty obviously a prequel. They're showing what appears to be the major getting her adult cyborg body for the first time and being recruited into Section 9 by a non-grey haird Aramaki.
People are complaining about the non-Yoko Kanno music and that the Major is doing a Kaneda (from Akira) cosplay with the red clothes.
I have confidence it will be good for two reasons.
1) Production I.G.
2) They didn't forget to have a shot of The Major falling off a building backwards.
I would rather have a full TV series than four 50 minute parts, but I'll take what I can get.
Maaya Sakamoto voice acting is controversial for some reason. I don't care.
There's also going to be some sort of GitS online "Hacking FPS". It will probably suck. If you want to play GitS: the game, just play Android: Netrunner.http://www.animenewsnetwork.com/interest/2013-02-12/ghost-in-the-shell-online-game-to-be-hacking-fps