Recs.
Updated
Unturned is a voxel based zombie survival game where you team up with your friends, in order to remain among the living. Fight off zombies. Gain XP to level up, and gather resources and weapons along the way.
SpecsUpdate
Pros
Pro Fair F2P model where no single person has a false advantage over anyone else
The game’s free-to-play model allows anyone to play free of charge; those who are willing to spend $5 get access to a separate server that grants double experience. So while it is not pay-to-win, spending some money will increase how quickly you can advance in the game.
Pro Well made maps where each is designed with purpose
Unturned is slightly different from other open world survival games, because it doesn't use randomly generated worlds. This actually is a pro, because the existing maps are very well made, well thought out, and overall having better design choices for worlds than say, Minecraft, Terraria, or 7 Days to Die.
Pro Fun and intuitive crafting system allows the player to explore tons of combinations of items
The crafting system can be used to easily and intuitively make hundreds of items. Combine two sheets of metal to make a saw, combine two sticks and a nail to make an arrow. Basically you can play around and test what kind of combination make what items, which is fun in and of itself.