thatgamecompany did flOw, Flower, and Journey as part of a 3 game deal with Sony. flOw was originally released as part of Jenova Chen's master's thesis and was reworked for their first release for Sony. This unfortunately means they are likely to remain exclusive to the Playstation3 platform for the foreseeable future.
Ico and Shadow of the Colossus were developed by Team Ico, led by game designer Fumito Ueda, and were released on the PS2 years earlier.
I know I read somewhere where they openly acknowledged their influence in the making of Journey, but it seems readily apparent that the emphasis on minimalism, emotional and musical immersion, and artistic stylizing are shared by both the development teams. I'll try to find the quote, it said that Fumito Ueda had played Journey and enjoyed it also.
It seems to me to be a game about the simple things so fundamental and central to the human journey that we tend to just take them for granted; the universal human experience of living.
All those first-person, competition-induced, shooting sexual metaphors that seem to dominate the gaming market, they are more simplistic in focus. Journey is simplistic in execution, but much broader in scope.
If we were to only focus on our sexual encounters (or metaphorically speaking; like being the hero/winner or having our 15 minutes of fame) as important moments in our life, then the vast majority of our lives would be meaningless and devoid of importance by comparison. There is more value in all the subtle, simple things that encompass the overwhelming majority of all of human existence.
It's like trying to explain the experience of drinking a fresh glass of water after journeying through the desert to someone who hasn't. It's all in the context.
From what I've seen, but I cannot confirm it, the artistic style seems to me to have a Shinto-esque inspiration to it that I really like. I also enjoy mention of Campbellian monomyth influence and mythology in general. I wish I could experience it myself, but I am without a doubt an admirer.
I've been reading a bit about Journey, but I can't play because I don't own a PS3. I do think it looks beautiful and from what I've heard about it it seems like a fantastic work of art.
I actually feel saddened hearing others talk it down comparing it to the latest first person shooter or whathaveyou like they can't appreciate something of subtlety. Most other games have a sort of unconcious sexual metaphor to them it is easy to understand why they're enjoyable, but it seems so shallow by comparison.