Osmos is a dreamy, relaxing game of space domination, which is quite unlike anything else and extremely addictive to boot.
In Osmos, you control a 'mote', which can absorb other smaller motes to grow. Your challenge, generally, is to absorb smaller motes, and grow enough so you are the biggest. The trouble is, you move by expelling matter, which shrinks you. You therefore have to move gently around, aiming to drift into the right motes, and do nothing suddenly. There is a variety of other motes to deal with, like repellers and attractors, which make Osmos more interesting, but never frantic.
This unusual action is accompanied by really beautiful minimal graphics and ambient music. It's extremely absorbing and really easy to get totally lost in the gameplay. Osmos has been excellently transferred to the iPhone's small screen. In-game instructions are excellent, and all the controls work perfectly.
Osmos is one of the most pleasing, relaxing and addictive games we've seen, and this iPhone edition is just as essential as the iPad, PC and Mac versions.