flOw = an experimental version of Pac-Man
Flower = a refined, perfected version of flOw
Journey = an online-enabled HD combination of Wind Waker, Ico and Shadow of the Colossus.
These comparisons may not be entirely accurate, but it's the closest way I could convey the changing trajectory of thatgamecompany's design philosophy. Journey is the most ambitious (and potentially revolutionary) undertaking from the independent studio, yet it also draws the most similarities to what many would call "traditional" games. Like most every other game, there is a humanoid avatar, controlled by analog stick. You jump. There's platforming. There's also an incredibly evident game-like goal: to reach the top of a mountain, looming in the far distance.
At its core, Journey can probably be best described as a platformer, with a clear objective: get to the end. However, thatgamecompany isn't simply focusing on a goal -- instead, the experience is geared towards its title. Players are dropped in a gorgeous psuedo cel-shaded desert world. The character designs evoke Wind Waker, but the mesmerizing cloth and sand physics make the world feel even more alive. Like Team Ico's games, there is an incredible sense of loneliness to the world: there's no life, no foliage to be seen. There are remnants of a world lost, with a beautiful tranquility.