Sanctum 2 is a bit of an interesting take on the Tower Defense genre. You still have to place down turrets and utility towers in order to corral and annihilate your enemies, but instead of being completely helpless when your defenses fail you also have a variety of guns to shoot the enemies with yourself! Its a small addition, but it really goes a long way towards easing some of the frustrations present in pretty much all Tower Defense games.

If this sort of gameplay theme sounds like something you would love to try out, you're in luck as Sanctum 2 is currently free to grab on the Humble Store. The offer will only last for another day and a half (or 37 hours to be specific), so make sure to grab yourself a copy as soon as possible. You don't even need to install it in order to own it forever, simply redeem the key on Steam and you'll be in the clear.

While you're there, make sure to also check out the currently ongoing sale as it sports a rather large assortment of games at an equally large discount. And with all of that said, allow me to leave you with a rather ancient gameplay trailer for Sanctum 2, just so you get a better idea of what kind of game it truly is. Have fun, and here's the video: