Bohemia Interactive has released a free version of DayZ. Sort of. It's MiniDayZ: a top-down, singleplayer take on DayZ's zombie survival.
The game was originally a fan project, but has since been taken on by Bohemia. You can play it in-browser, although first you'll need to register for a Bohemia account.
Once inside, you'll be confronted by familiar needs. Your food and water meters will be dropping, and so you'll need to leave the coast to scavenge for items. Also: there are zombies. While you can punch them out slightly more effectively than in DayZ proper, doing so will almost certainly cause bleeding. Both guns and melee weapons can eventually be found.
It's also a bit like DayZ in that the inventory is a pain in the ass. Still, it's a charming recreation, and a nice web-based distraction for when you're not able to journey into the human-filled world of the main DayZ.
