Jenova Chen thinks that video games don't access enough of the human emotional spectrum. Sure, they do revenge and aggression well but they struggle to handle love or other kinds of deep connection.
That's why all of the games spearheaded by Chen -- Flow, Flower and, most recently, Journey -- have all proceeded from a clear mandate of wanting to expand the emotional vocabulary of video games. He talks about that on an interview with Gamasutra:
"My biggest complaint for computer games so far is they are not good enough for adults. For adults to enjoy something, they need to have intellectual stimulation, something that's related to real life. Playing poker teaches you how to deceive people, and that's relevant to real life. A headshot with a sniper rifle is not relevant to real life. Games have to be relevant intellectually. You also need depth. You have the adventure -- the thrill of the adventure -- but you want the goosebumps too."
Chen also connects the limited subject matter to how much bigger games tends to cost:
Right now, games are so expensive; they're 60 bucks. If they don't let you kill over a thousand people, the game is going to be dead within two hours. Then they have a problem justifying 60 dollar prices...
The developer also alludes to the fact that he and colleagues at ThatGameCompany are working on something new but need financing after the expiration of their three-game deal with Sony.