UPDATE 1.5: Change Log (Steam Leaderboard)

Steam Leaderboard You must earn at least 3 Stars to qualify for a Leaderboard entry. There are Leaderboards for all 27 levels in the game.

You should exit the Steam client, and restart Steam to make sure the game is updated successfully. Once the game is updated, play the game until you have earned 3 stars on any level. You can then check your Leaderboard results by visiting our ‘Global Gameplay Stats’.

http://steamcommunity.com/stats/462960/leaderboards/1436096/

Best of Luck!