cool story bro, please, tell us more
These "MMO zombie survival" games really originated with the Arma 2 Day-Z mod. Even being a mod it was a great game and tons of fun which is why it spawned a stand-alone version which eventually would be its own title, a full price triple A game.
Bohemia Interactive, developers of Arma series, even bought out the developers of Day-Z so they could publish the standalone version of the game. This has been in development for over one year.
Sergey Titov, creator of the infamously horrendous Big Rigs, created his own game development company to create War-Z (now known as Infestation: Survivor stories due to move licensing with the film War-Z). This game has been in development for approximately 2 years. Titov is supposedly no longer on the team and they are currently making a follow-up game with less restrictions since the developers left their publisher whom they were supposedly having creative differences with.
Sony is now taking a copycat approach to cash in on the popularity of this genre by creating their own Free 2 Play game. Unlike the games before it, it's very early access and virtually unplayable. Once it is released it will be pay to win.
In summary, the best option for gamers in this genre would be Infestation Survivor Stories ($3.75) or the Day-Z mod (free as long as you own Arma 2 + Operation Arrowhead expansion, the combo often goes on sale for ~$5). Day-Z Standalone is leaps and bounds beyond H1Z1 (probably 1.5-2 years dev time) and you can play forever for $34.99, less during steam sales. There are also other options such as Nether or Rust. I'm not sure why anyone would pay $20 to play H1Z1 pre-alpha when it will eventually be free and pay to win, and is far behind the competition.