Osmos makes you feel like you should have paid closer attention in Physics class!
This is a physics wonder to say the least. After doing the tutorial levels you think the game is going to be a cakewalk! But you soon learn that the game has much more depth and playability. Several levels will take you hours of calculating to beat. More than one I found myself pressing Ctrl+R to restart at least 30-40 times before I got the hang of it. Other times it was just a matter of luck that I even beat it at all.
Graphics:
They're nice, but very limited. Make sure you're LCD is out of the sunlight because it's near impossible to tell a borderline "I can absorb" from a "Will absorb me" and many levels you'll need to make the differentiation. Overall, there's not a lot of depth to it. There's basically about 6-7 different creatures that you will see the whole game. Some is AI, others are just random blobs floating around. The good news is, graphics aren't your prime focus of the game so it's not a big issue.
Sounds:
The soundtrack is very nicely done. It helps to relax you on very difficult levels. I'm a little sick of games filling their soundtracks with hardcore trance music all the time, and it's a nice change to find a game with a more soothing soundtrack.
Playability:
If you haven't switched to a laser mouse yet, might be a good idea. There's many times where you have to be very precise in your movements. A matter of a few millimeters is enough to go from doubling your size to restarting the level. Another issue is for all you impatient people out there. I'm one of them. Even running the game at max speed, sometimes you have to just put down your mouse and wait around for something to happen. I find this especially true on some of the levels where you're orbiting a sun.
To Sum Up:
This is a great game to pass the time for a few hours. This is going to be in my "Put it in a box and forget about it then find it a year later and reinstall it" type games. The easiest way to describe this game is a cross between the early levels of "Spore" and the game "Crayon Physics". Go out and give it a try!