Google has outdone itself with its latest playable Google Doodle, unveiling a card game that will return every month with new features to unlock. The Doodle is called Rise of the Half Moon, and coincides with October's half-moon phase, while future iterations will presumably return for half-moon phases in other months.

The game has players squaring off against the Half Moon in a card-matching game, with multiple ways to build up points. Score one point for matching a moon phase with the same moon phase, or two points for matching it with its opposite to create a full moon. However the most points can be racked up by creating lunar cycles of three cards or more--but your opponent can snatch your points off you by adding more cards to a cycle.

If you win three games against the Half Moon, you can unlock a special power-up, with four available to be collected in the 24 hours this Doodle is available each month. Google has added some extra information about the Doodle on its Doodles hub, including credits for the team who developed the game, and some pictures showing the development process on Rise of the Half Moon.