Most video games in the classic arcade mold inundate you with high-speed action and require you to have ultra-fast reflexes and adjust to a constant barrage of fast-changing images. Osmos goes the other way: It rewards patience, finesse, and delicacy, and does so in a fascinating, fun, and involving manner.
In Osmos, you play a... sort of...blob...thingy. Maybe you're a ball of plasma. I don't know. You move by ejecting matter from yourself. As you move, you shrink. Your goal is to absorb any item smaller than yourself, while avoiding being absorbed by any item larger than yourself.
See the challenge? As you move, you shrink. So you might end up smaller than your target by the time you get there. You must use only slight puffs, relying on slow drifts to push you into position--but meanwhile, all sorts of other things are drifting around, and many are larger than you are. So you expend more 'fuel' to get away from one, shrinking yet more...
As you absorb things, you get larger. The game helpfully keeps you from having to guess which things will absorb you and which you can eat; those smaller than you are blue, those larger are red. Seeing a sea of red blobs fade to blue as you scoop up your prey is very rewarding.
There are challenges beyond that. The early levels feature 'repulsor' blobs which will force you away if you move too slowly; you must burn a lot of fuel to reach them and eat them. Other blobs will suck you in, or have other game effects. Through it all, soothing new age music plays.
Osmos is an original and fun game. Though still somewhat early in development, it has amazing potential. This alpha version contains only a handful of levels and the full release is not scheduled until summer, so the fun can be over pretty quickly. And it can be a little laggy in Vista. On the other hand, it's free...and did I mention that it's fun?