Generations is basically a localised version of Monster Hunter X, which launched in Japan late last year. The game is also launching with a collaboration with the Fire Emblem series, which will manifest in the form of a special armor set based on Marth that will be downloadable upon release.
Also, those who own Monster Hunter 4 Ultimate (or have played it) will unlock special content in Generations, via their save files. We assume that these would be either special armor/weapons or bonus missions but there’s been no confirmation as of yet.
No pricing details for the new release but we’ll be sure to let you guys know if we hear anything new.