Unturned is a survival zombie game with minecraft style graphics.
You become a survivor in the zombie infested ruins of society, and team up with your friends to remain among the living.
Don't get fooled by the graphics, it's a hard survival game with crafting.
The game is completely free (not just "free-to-play").
If you want, you can spent once £3.99 for an Unturned Permanent Gold Account Upgrade, which gives you
-Golden name in chat and player list.
-Extra skin colors, hair and faces.
-Access to special Golden servers.
-Suit and shades on Golden servers.
-Extra loot drops on Golden servers.
-Double experience on Golden servers.
-Enhanced sleek darker user interface.