From gamerstemple.com: Kingdom Hearts 3D is a no-brainer for fans, but those new to the series would be better served by playing almost any of the past titles or spin-offs.
Well yeah, it is a series... They're not standalone games like Final Fantasy, you NEED to play the others before playing this one. Birth By Sleep < Kingdom Hearts 1 < Chain of Memories < 358/2 Days < Kingdom Hearts 2 < RE:Coded < Dream Drop Distance < Kingdom Hearts 3
N4G is a community of gamers posting and discussing the latest game news. It’s part of NewsBoiler, a network of social news sites covering today’s pop culture.