A hybrid game hybriding it up.
Sanctum 2 is Free on Humble Bundle Store. All you have to do is sign in, add it to your cart, and check out to get a key for it. But act fast, since It’s only free for the next day and some change.
Sanctum 2 is the sequel to the world’s first Tower Defense/FPS hybrid game. Pick from four unique character classes and protect the Core! Outfit your character exactly the way you want through the new and extensive customization system. Choose your own loadout of towers, weapons and perks, but choose wisely because you are humanity’s last defense against the unrelenting hordes set out to destroy it.
Sanctum 2 is a new game completely rebuilt from the ground up using community feedback and innovative design to really push the bar of what an indie studio can do.
In Sanctum 2, you will utilize elements from multiple gameplay genres to succeed. Construct towers and walls during the building phase before the enemies attack, then jump into the fray and blast everything to pieces in FPS mode. You can progress through the single-player campaign yourself, or play with up to four friends in co-op!