7 Days to Die is a very fun game and is going to be an amazing game when the developers finish all that they have planned. Currently gamepay consists of gathering resources with which to craft and build. If you need metals, coal, potassium nitrate, and that sort of thing then you mine it. If you need wood you chop down trees. To get weapons, recipe books, and any of the other items you may need you will typically raid major cities or towns that are zombie packed.
There isn't much more to it right now aside from gathering the toys you want, things like SMG, Chainsaw, Auger, Sniper Rifle, or Rocket Launcher and then building your base up to survive the massive feral night hordes that want to eat your brains.
HOWEVER, the devs say that their inspiration for this game came from Fallout 3 and Minecraft. They want to merge the two worlds. What's planned is NPC's featuring quests and storylines to follow, vehicles, metallurgy, electricity and generators, and a full blown living world of NPC survivalists to interact with.
This is one of the best co-op games I've ever played. The zombie shrieks and growls will send chills down your spine as you and your friends feverishly repair your damaged structures as the zombies break through. You will feel an immense sense of accomplishment after you construct a worthy defense structure and successfully fend off a zombie horde.
My background in games is Eve Online for 10 years, some WoW mixed in, and I love open world games and strategy games. This game does a good job of satisfying my need for killing, surviving, strategizing, and progressing.
The only downside to this game, IMO, is that this game doesn't have intentions of being a full blown MMO. The game is on player owned servers with a maximum of about 64 players. This game could be the best game ever made for me if it were an MMO. But this is a great game, with one of the best communities i've ever been a part of, and a development team that's dedicated to making their dreams become reality in the form of a fantastic game that you should own!!