This is nitpicking; it certainly hasn't stopped me from enjoying State of Decay. But it does get a little annoying/old when the first forty minutes of most zombie games/movies start the way, with complete ignorance. For me, it ranks up there with acting like it's a huge fucking downer when you suddenly get super powers.
If there was a zombie outbreak today, most people would pretty much get it from day one. If the first zombie you saw wasn't too visibly fucked up, there might be a moment of "Oh what's this weirdo doing dressed up as a zombie", but as soon as you knew it was real, you'd know what the deal is. You'd still be like "How the fuck is this possible", but you aren't going to derp around about them. We've been exposed to enough zombie media and variations of it that we'd have a grasp on the rules.
Regardless, State of Decay is incredible. I am absolutely invested. Don't get me wrong, there's some technical issues. The framerate can take a nosedive, some zombies clip through walls. I once saw one of my survivors at basecamp lay down in the yard, like he was going to bed, and then float inside the house all the way to the bedroom. But the game's problems are dwarfed by everything State of Decay does well. And that is mostly in creating an amazing, authentic zombie survival RPG.
I don't know how many hours I've put in so far, but ten would be a reasonable guestimate. I don't feel like I'm even close to being done. The game rarely forces you along any particular narrative. There are plot point missions that introduce you to something new from time to time, but it's up to you when to undertake them. Which is good, because shit gets hectic.
The game walks a really amazing and fine line between order and chaos. I currently have my survivors set up in a home that I've been working on upgrading and fortifying. Between scavenging food, medicine and building supplies, tracking down my fellow scavengers that get themselves into a jam/lost, dealing with mood issues and potential crises with my individual survivors, making sure that my survivors are rotated out regularly so they can rest and heal up, and making sure too many zombie hordes/infestations don't build up around our camp, I feel like I'm constantly walking along the edge of complete ruin. It's exhilerating. You have to completely scramble just to tread water in most cases.
It's the perfect feeling you want in a game like this. It never feels completely hopeless, but at no time can you relax and rest on your laurels.
You'll find yourself getting attached to certain survivors as you play... not so much their personalities, but definitely their experience and skills. Since once they die, they're gone for good, losing a particularly leveled up character can hurt. You can take another survivor back to collect the fallen's comrade's supplies, but it's a small consolation.
Just about everything in the world is finite. When you start the game, there are a limited number of cars that exist. There will never be more cars. Cars take damage, and if you ruin one, it's gone for good. You can upgrade your home base with a workshop that will help repair a car parked there overnight, but you'll likely find yourself treating your vehicles with as much respect as your situation allows. Sometimes you have to ditch one and proceed on foot... the cars are always right where you leave them, so that's neat too.
Resources are also finite. Once you've scavenged a building, it's cleared out. Food doesn't magically respawn. There are tons of buildings in the game, and you can enter just about all of them, so there's a level of strategy to scavenging. If you bring back more resources than your basecamp can hold, the extras are lost. You've essentially wasted really valuable food or ammo. So do you start scavenging the places closest to your home, where its the safest, or do you start far away and slowly work your way back. Are you prepared to move basecamp once you've exhausted a particular area?
I am completely blown away by the depth and attention to detail in State of Decay, which is a downloadable XBLA title. The game is $20. That's a steal for the amount of fun and gameplay it delivers.