Developer: Hemisphere Games

Platform: Windows, Mac, Linux, iOS

Price: $10 (for Windoes + Mac + Linux versions)

    $5 iPad, $3 iPhone

Osmos is sort of a puzzle/arcade game. You are this circle in a world full of circles of all sizes. Whenever two circles meet the bigger one absorbs the smaller one. You move around by expelling some of yourself in one direction to move in the other direction -- for me it's like playing in a frictionless universe. Naturally as you accelerate you get smaller so you have to be careful. To help you our circles bigger than you are red and ones smaller than you become blue.

The objective in each level is usually to become the biggest object. Some levels you have to eat another entity that is also self-mobile. But most circles are dumb and only move because something else pushes them, such as when you accelerate and hit them with your exhaust.

There are about 40 levels and there are variations on the main theme. Ambient levels (one is pictured above) have dumb circles starting out unmoving. Some ambient levels have antimatter circles -- when matter and antimatter collide they both get smaller. The harder levels you have to be careful to slowly push bigger circles out of the way so you can get at smaller circles.

Force levels have gravity circles. I think of them as suns as many of the levels start out with all the circles orbiting the gravity circle. (Note you can zoom in and out and speed up/slow down time using the arrow keys. I especially like the big ambient levels when you can zoom in and see your tiny circle next to these gigantic circles.)

To help you out force levels show you your expected path influence by gravity, though it might change if you absorb circles along the way. If the path is blue you're fine and if red you will collied into the gravity circle or the side of the screen (in these levels the walls absorb you). It gets more challenging when there are multiple gravity sources.

I like force levels that start out like a solar system. Everyone is in a stable circular orbit. As you move around you get different orbits and crash into and absorb other circles. The game almost becomes a solar system simulator.

Sentient levels have other self-mobile circles. Most of the time those circles are also eating other circles so it becomes a race. You have to eat and grow before everyone else does and leaves you nothing to eat.

The soundtrack is rather soothing. Several different mood music tracks, mostly reminding me of space or water.

There are some achievements. No difficulty levels. Graphics are really good though hard to tell in these pictures. It's probably a 10 to 20 hour game.

I think the only drawback is that the game is rather CPU intensive.

Osmos is a rather original game with smooth gameplay, well done graphics and sounds, and a good polished feel. At $10 it's well worth buying.