for anyone who doesn't know,
DayZ is a mod in alpha stage for ArmA2 and it's expansion Operation Arrowhead.
from Wikipedia:
DayZ places the player on a beach in the fictional post-soviet state of Chernarus, where an unknown virus has turned the general population into zombies and devastated a large military force, likely called in to contain the situation. As a survivor with limited supplies, the player must search the world for supplies such as food, water, weapons and medicine, while killing or avoiding both zombies and other players - in an effort to survive the zombie apocalypse.
The game attempts to portray an authentic scenario, with the environment having many different effects on the player. A player may receive bone fractures from repeated damage to the legs, go into shock from unexpected ambushes, receive infections from both infected zombies or diseased players, or even spontaneously faint due to a low blood pressure. Thirst and hunger must be regularly dealt with by finding sustenance in either cities or in the wilderness, with body temperature playing another key part in the character's survival.
it has a steep curve, and after a few days I'm only starting to get the hang of things. it is in alpha, but there are a few minor to major annoyances. zombie pathfinding is atrocious and is sometimes difficult to escape them. the netcode isn't the best, clunky inventory management, and visual glitches are everywhere. it relies on Arma2 files, so any Arma2 patch has an effect on DayZ (recently nerfed pistols in Arma2 carrying over to Dayz is a particularly painful occurrence to come to mind).
aside from the major bugs and glitches you are spawned without any way to defend yourself. if you don't find an early hatchet you're going to have a tough time as you have no choice but to run away from zombies (which will attract more zombies). it's easy to get lost, finding an in-game map isn't always easy so often you have to resort to an external map. and even still the in-game map is a bit lacking.
at times, the zombies are only a relatively minor inconvenience. the real enemies are players. never have I felt such terror from encountering another human in a game before. it's hard to describe, but every time I'm faced with a decision to kill or I'm being shot I get this terrible rush of adrenaline. my heart starts pumping and I start sweating. I've never felt dying or killing in a game like that before. I try my best not to kill, I feel far too guilty murdering people. most players will shoot on site, mostly for fun other than survival. so it's basically a survival deathmatch at times. cooperation between strangers is highly rare, but it's very memorable when it does happen.
and speaking of memorable here are a collection of some great DayZ experiences I've found on reddit or elsewhere:
http://i.imgur.com/KTuai.jpg crying in video games
http://i.imgur.com/UyyWd.jpg newbie meets a commando from north
http://www.youtube.com/watch?v=oQQ4N1kMv9o guy gets picked up in a bus and a group forces him to fight for his life.
http://www.youtube.com/watch?v=M2hojPlvVPI someone infiltrates a large group in a major town. mass paranoia ensues.
http://www.youtube.com/watch?v=pR02qCEVUAM unarmed survivor makes friends with strangers
http://www.youtube.com/watch?v=NnOmXSUVAB8 firing squad saves survivor in distress
