UnityAGK is a Complete Game Project and Tool to help you easily create Tile-based Action Games, such as Hack and Slash or Shooter Games. Create a Gauntlet-style Dungeon Crawler, Fantasy Hack and Slay, Sci-Fi Shooter, or even a Zombie Game without Touching a Line of Code! - Check out the Playable Game Demos!
Zombie Quarantine was recently Greenlight by the Steam community. It will be releasing on Steam very soon.
If you want to play Zombie Quarantine now and can't wait for it to release on Steam then you can purchase it on Desura Indiedb.com
Updates fleshing out the game and improving the gameplay dynamics will be regularly released.