the longer the boardgame takes, better i say!
basically a zombie survival game with a pvp option. with bad graphics. a ton of fun!
In single player, you try to gather resources like food (you will find in kitchens) and weapons. Until you can become self-sustainable.
In multiplayer, you can join a pvp server, where you try to survive and gather resources while also trying to kill other players. There are PvE servers too where you work together to survive. Unturned also attracts a lot of role players, which can be a ton of fun too.