This is an interview with the developer and aside from the single and coop part they said they are planning to release the first half of 2015 so january to june(most likely march
)
http://gamerant.com/splatoon-single-player-splitscreen-multiplayer-details/
here is the interview 
Bets:
(Won)Bet with TechoHobbit: He(Techno) says 10 million by January 1,2014 I say 9 million by then. Winner gets 2 weeks of sig control.
(Lost)Bet with kinisking: I say Ps4 will win April NPD while he says Xbox One will win it; winner gets 1 week of avatar control.
Raichu's First Series:
Official Ni No Kuni Fanboy:
Familiars Captured:37
Game Beaten: 2 times almost
Times I got teary during some scenes: 3







