I made a test run yesterday with some never played and already started games and I found the Recent Games section pretty much not working at all. The achievements unlocked just fine (even if it took like 12 hours to refresh them) but the Recent Games doesn't updated at all. My played games number updated from 108 to 110 just fine in the collection summary, but those games are not in the Recent Games section, also I didn't see a message on the friends feed about starting new games, like TrueAchievements does - not sure if that function will be available for this site. None of the games I played yesterday - including Civ V - poped up anywhere as recently played. As you said last played info is not in the Steam API, which is kinda odd as the raw info can be seen right next to the Play button on the game's page.
