After Tuesday night's Steam maintenance, we noticed that many leaderboards appeared to have rolled back to an earlier state. We're waiting to hear back from Valve to find out what went wrong, and whether they can restore the lost scores. In the meantime, we've created a new beta branch called leaderboard-fix which, when used to view leaderboards in-game, will attempt to re-upload any of your scores that are missing. This fix will eventually be rolled out to everyone, but you can try it out right now if you're desperate to get your score back. We've also started making our own backups of the leaderboards, in case this happens again. Sorry for the inconvenience!