I played for a little more than 90 minutes on n3DS, survived 5 days in single player.
Before you start you can choose between singleplayer or multiplayer (up to 8 players), the latter divided into local, internet or friends only (yay!).
In the options you can invert x or y axis and adjust sensitivity, use c-stick for camera and aiming if you own a n3DS and turn manual camera or chat on or off. The button layout can't be altered.
The game has no story or missions, you start somewhere on the arctic island with nothing in your inventory and no idea where to go. It is just open world sandbox survival. Find stuff, tend to some simple vitality stats (hunger, thirst, bleeding), do not get eaten.
You have no skills whatsoever, chopping wood, light a fire, charge your phone or sleeping undisturbed is handled via mini games that sometimes require some timing. When aiming, the game zooms over your 3rd person shoulder. You can move slow and even strafe when aiming with a rifle or looking through binoculars and only there you can adjust the camera on the y axis to look up or down, which unfortunately doesn't work when you are just walking or running.
When finding a new item, you get a short description how to use it. I found a bear trap for example and it is handled differently than other items or weapons. The manual provides no description for those things. Items respawn at random every new day in indoor locations. Each bed can only be used once a day.
Zombies shamble around aimlessly but they react to noises you make and they can see you. They do not follow you over greater distances, but they run a little faster than you for a short time. They are not very dangerous most of the time but if you are not careful and tired, they can kill you. They only hit you once and injure you, they stand still and let you escape afterwards. You bleed, but are not infected or something like that.
I don't know if they have hitzones or hitpoints, some were dead after one bullet to the chest, another one took three bullets. Zombies do not seem to leave items.
Technically, the game is no eye candy with its low poly models without textures and no effects. But it has a remarkable atmosphere, the framerate is quite ok (although not stable) and you can see quite far which is relevant for the gameplay. I had a conversation with the developer on Miiverse, he said on n3DS the game runs a little smoother. Thousands of trees build a credible landscape, unfortunately they are made of air, you can clip right through them.
I can't say anything about the performance in multiplayer yet.
The environmental sounds are moody with the wind blowing and some occasional animal noises and zombie groaning.
Is it any fun? Well, I like it. I see no reason why I should not have spent 2,99 on it. It is enough for a few hours, I have not seen the whole island, not even half of it, used no vehicles due to missing items and did not play with friends. Maybe my brother has time this evening, I'd like to try it out.