Go with the flOw, and be in the know.
First off, I'll start with the graphics. While this isn't exactly a game that will make your eyes pop out of your skull because of the amazing graphics, they are.. basically as good as they can get for this game (being that the nature of the game is basically lines and dots). Very smooth edges, and virtually lag-free gameplay (I only experienced a little frame skip when there were about 70 or so "edibles" on the screen at once). The backgrounds are a bit overwhelmingly colorful sometimes... but it's a very smooth game all in all, and it is well-deserving of the name "flOw".
Now the sound... Amazing. Both beautiful, and eerie at the same time. It's still pretty relaxing, and the orchestra-themed music is a great touch, to add even more atmosphere to the game.
As far as the gameplay goes, its relatively simple, and only on some parts, did I find myself running into a bit of difficulty. Also, some of the forms (5 in all) are easier to play than the others, to to each having its own special ability. So naturally some abilities are better than others. Also, the two player co-op can be fun, but the lack of split-screen makes it a little frustrating at times when both players go opposite directions. (the screen doesn't pan out).
and finally, the controls. They work EXCELLENT. It doesn't take much movement at all to control your creature. I find it easiest to just rest the controller on my fingertips, and roll it around, kinda as if you were tilting a hot plate. I use R2 for the action button, as i can easily just barely press it (due to its great sensitivity) and take action. It took me about 10-20 minutes to get used to controlling my creature, then it just got easier and easier after that.
All in all, its a great game for $8.00. But I would like to see more challenge, and more substance to it.