When Sanctum arrived in 2011, it was a breath of fresh air for tower defense players discontent with simply watching the action unfold. The title features the ability to jump into the action and help take down the invading hordes via a first-person view.

If you missed the first Sanctum, it's available for the reasonable sum of $9.99 on Steam. Sanctum 2 will be out this summer on PC, Xbox Live Arcade, and PlayStation Network.