fl0w's unique indie art design and relaxing soundtrack are not enough to salvage much depth in this game.
As more creatures are eaten, you gain specific parts of their bodies and structures making you bigger or varying in colour. This "character-building" is tied to the background music and you will notice changes depending on how the character evolves. This may sound unique, but there is little variety in the sound of the game. The songs are soothing and relaxing but are more likely to put you to sleep than motivate you to continue playing the game.
Half a dozen creatures are avaliable in the game but you're only able to play each as they're unlocked. Unlocking means completing the previous creatures stages, one at a time. Each varies in shape and has a unique special ability, for example, the snake gets a speed boost, the manta sucks creatures into it etc. All of these lifeforms evolve different from one another and have different coloured environments from their predecessors.
fl0w is a difficult game to describe, it lacks story and subtance, seemingly on purpose, in order to create a soothing atmosphere and environment, categorizing it as more of an experience as a game. Unfortunately, it doesn't remain a very good one as the shallowness and over simplicity will not hold one down for more than a span of fifteen minutes. With so many other fleshed out products avaliable on PSN, I can't justify the value of fl0w.