I love this game. It's still in Alpha, but playable with a few bugs (sniper rifle).
I would compare this to a L4D2/Minecraft combination. With that being said, the game can get frustrating at the begining, but once you have a system down it becomes less frustrating and more resource stockpiling. In that it is a combination of those games, you will see alot of enemies that are very simular to L4D2 enemies. Cops are almost identical to the Spitter in the series. A few enemies are quite unique and can be a headache while trying to gather equipment. The idea you have to build everything is quite simular to Minecraft, except the list of available items to create and thier plans are all right there, removing the need to go wiki to look up ingredents. The game does last longer than 7 days as a contridiction to the title, which is nice.
There are many different options when starting a game. From single player to multiplayer, random map or Storyline map. The options of what happens to your gear when you die, how often items reset, how often airdrops happen, and even the legth of each day (way awesome).
Some very interesting ideas that the game does offer is the ability to become infected, suffer from injury and disease, and attract zombies with some of the items you can have in your inventory. The ability to go into "sneak" is almost exactly like Skyrim, to include the HUD icon.
The multiplayer portion of this game is what seals it down as a great game. When set up right it makes things interesting for a 4v4 multiplayer map as teams can fight over resources in an area, all while also trying to keep from being killed by zombies.
The down side to this game is that the crafting time can be really long and some resources aren't easily available as fast as you will go though them (brass and gas). If you don't have a good balance of difficulty you can find yourself spending your time just grinding with little to no challange.
Tips: Leave your zombie run to Default, set your bag to "delete" when you die, and set your day/night ratio to 50%.