Block Fortress is a great mix of tower defense and first-person shooter that lets you build a home base with turrets and other defenses, then play in first person while you help defend your blocky base. It's an incredibly deep game, but the way the developers named the game types is a bit confusing on first play.
The graphics in the game are almost exactly like those in the hit game Minecraft, with tons of different block types to unlock and use to defend your fortress. Fans of Minecraft will feel right at home during the building phase of the game, with fortress walls, turrets, and power sources, that are all placed block by block. There are 30 different wall types with weak concrete walls that only a few hits will destroy, up to Tech Metal walls that are much stronger (and more expensive). You also get 16 turret types to choose from as well as 11 guns you can unlock to equip your character before the big battle.
You get three different game types in Block Fortress along with six different terrain types to choose from. Survival challenges you to start small, buying turrets and defensive blocks with limited funds, then start the first round defending your base against attackers. When you have killed a certain number of enemies (called Goblocks), the attack phase ends and you're able to use earned cash to rebuild and fortify your base. Survival continues on with rounds of this defend-and-build mechanic until you're finally overrun by the Goblock horde.