Citando a A jesucristo:
With MGS4 now complete, Kojima has proclaimed himself done with that series and looks forward to continuing up on past series and creating new ones. Zone of the Enders is one such series. ZoE is a fast paced mech fighting series, and originally launched for the PS2 in spring 2001. While the first one(you know, that free game you got with the demo of MGS2?) was welcomed by a mixed reception, the second Zone of the Enders is largely considered one of the PS2?s most underrated games.

During an interview with PSM UK, Kojima told them:

?I would like to say that Zone of the Enders is quite near the priority list? [after MGS4] it might be good to change to outer space or robots or things like that for a change?