I was bored so I decided to actually try this out after watching a few videos online. Many aspects feel very Minecraftish (crafting/building) and many feel DayZish (looting, etc). Graphics aside, it has a lot of potential and seems like it could be a blast doing co-op/multiplayer.
Anyways, the day/night cycles are pretty fast (approx 1 minute gametime = 1 second real time). During the day (or when exposed to a light source, like a torch), the zombies are your typical slow Romero zombies. As such, this is your best time to build/look for resources/cut down the zombie population. When it gets to be night time (I think around 2000/2030 hours or so) or inside a dark place (a home, for instance), the zombies become Dawn of the Dead remake zombies that run like 4x your top speed and do lots of damage. As such, your best bet is to find shelter or fortify a spot so you can last the night. The zombies can sense you on the Z-axis if you are a few floors up and they will go apeshit trying to get to you, which results in them breaking through doors/walls/etc. If a building takes too much dmg (key support beams get destroyed or walls), then the whole structure can collapse. During the first night or so, you can probably survive NP in any structure that has multiple levels (attic is best), but more and more zombies spawn each night so eventually you will need something strong. As you go, you can gather stuff that lets you craft. For instance, if you knock down a tree, then you can use the wood to make various wooden items, including sticks. Scrap metal can be turned into iron ingots, which in turn you can use with the sticks to make a pickaxe or wood axe. There are all sorts of recipes. Some raw materials, like stone, you can build with as well. If you make a sleeping bag and set it down, it acts as a respawn point.
By day 5 or so, I decided to make a bunker underneath a garage (be sure to make defenses where you are digging, they will come into the hole). Once I got deep enough and made a large room (oil barrels can help you clear lots of room, but you need to be way the fuck back when you shoot it or you will frag yourself), I sealed myself in with stone blocks and dug through the night. Eventually I had multiple chambers /w locked metal doors and I actually fortified the garage itself by basically encasing it in stone, which is very hard for zombies to bust through in this build. Around 0730 hours, its light outside and the zombies will be slow again. On day 8 I had looted a good chunk of the town I made my bunker base in, so I decided to head to the desert to get special resources to make stuff like TNT (I also needed gasoline for my power digger/auger). It got dark out when I got to a gas station, so I had to craft a ladder to get on the roof and had to use some stone to make a mini-fort/tower (zombies sometimes warp through the floor). It's definitely cool and in the next build they are going to make tougher zombies (climbers, acid spitters) so you can't just AFK through the night once you get a solid base setup. I do like the fact that you have to plan ahead and be mindful of the time. If you get caught outside when it's night, you're pretty much screwed.