Campaign
Although vaguely promised during E3 2013, about 4 months later the development team has unveiled the campaign mode for Splatoon. It's still a concern as to how much content is going into the campaign, or whether it is a rushed afterthought to the multiplayer arena style gameplay. However, it looks like there are bosses, platforming, unique levels, and some sort of narrative. We shall see how much of a campaign EAD delivers.
Amiibo
Nothing has been announced, but considering the Amiibo suits in Mario Kart 8 by EAD, it would make sense for them to do the same in Splatoon. Your characters or Miis can have Captain Falcon, Fox, Samus, Luigi outfits during the multiplayer. This is all just speculation, but it just makes sense considering it's a big multiplayer game and Amiibos are going to be supported heavy by EAD.
Staff
Producer: Hisashi Hogami
Director: Tsubasa Sakaguchi, Yusuke Amano
Program: Shintaro Sato
Art: Seita Inoue
Music: Toru Minegishi