The game's really fun and delivishly clever in places... and even better, it's a PC game that gives achievements. They've been around a while - Universe at War, Section 8, Battlestations Pacific - but there seems to be a new trend in downloadable retail and/or arcade titles.
Osmos was a part a collection of games release around Christmas - Tinker, World of Goo, Where's Waldo, Mahjong Wisdom - that are PC-based Live-enabled games. Since they pop achievements like 360 games, I would think they'd show up in the feed and become part of my gaming events. There are not appearing, it seems, even though the sister site - 360voice - displays them in addition to my normal 360 gameplays. Is it possible they are being filtered out for being on the PC?