In a New Yorker piece covering Journey, Flower, and Flow developer thatgamecompany, the publication got a few more tidbits out of co-founder Jenova Chen regarding the team's next game. In line with his prior comments about it being a "natural evolution," Chen referred to the project as "the bastard child" of the aforementioned titles and compared it to seeing E.T. for the first time. Themes like self-reflection and nostalgia are said to be present.
"A lot of people asked us why Journey didn't let them play with friends or family, and obviously we had a reason -- because that would have defeated the purpose of the game," said Chen. "But for a game to be truly be accessible, to both children and adults and to men and women, it has to allow people to play with the ones they love." The new game will do exactly that.
Conservatively, this is still two years off and thatgamecompany hasn't pinned down how players will interact with one another (though a system of non-verbal communication will be implemented). Regardless, I'm very much looking forward to it. After attending E3 2013, Chen said he was "proud to see that no one is doing what we're doing, but also worried because I know why. It's risky."
A Journey to Make Video Games Into Art [The New Yorker]