Good co-op survival / building games?

Unturned is simple but kind of fun, unless you're looking for hardcore survival.

I would definitely suggest looking at Terraria, really cheap game when it's on sale and it has unbelievable amounts of content.

You might also be interested in Rust, it's co-op and survival but you'll also be playing with others on the same server.

Dying Light is good.

• Space Engineers but may not be what you looking for.
• Ark Survival
• Killing Floor 1 & 2
• Borderlands 1 & 2

Starbound
Factorio
(not survival&building but co-op-fun) Payday 2

Yeah DST is nice, Terraria is a very good game. Looks like crap from the store page but once you play it, you get hooked.

I haven't encountered any bugs so far in 7 days to die, but yeah I agree that the game does look and feel unfinished.

Wait wait wait, Fortnite is actualy out at last???? And 7DtS is finished, you can safely buy it. Before playing Dying Light, play the Dead Island games , 4 player co-op. Both Killing Floors have great survival co-op. Dead Rising 2 is realy fun co-op, Double Dragon Neon is fun cooperatively, Red Alert 3 is good in co-op, could always play one of the many battle royal friends as a team. Could play Rainbow Six Siege and Wildlands as a co-op team. You know what? Just press on the co-op tag on steam and look at the games yourself, easier that way.

It isn't necessarily good, but CastleminerZ is extremely fun to screw around with friends. It's fun for a few hours then it gets old and you've done almost everything. I believe it was dirt cheap for awhile and you could probably get a 4-pack for less than $2.

7 Days to die is a lot of fun but i cant run it as smooth as i would like. Still a fun game though :)

+1 for terraria
although I can't speak for the multiplayer part (you need friends for that :/ ) I have 800 or so hours in the single player version of the game

I love 7 days to die. I played it very long with a friend on a private server.

Good co-op and survival, although not building - killing floor 2. I started playing it recently with my friends and it's really well done, ESPECIALLY on your own server with custom maps.

7days to die is rather good and rather difficult. I love it.

if you're concerned about bugs or performance issues, especially performance issues, I'd avoid ARK. Even on pretty high end systems it's very poorly optimized.
Also setting up a private server, almost a necessity since the existing ones tend to be very hard to do any early game stuff on, is a massive headache.
I think 7 Days to Die has deeper mechanics and might not suffer from the massive escalation curve ARK does. After almost 100 hours on pretty much one server my buddies still can't even begin to take down the first arena boss without serious modding. I personally ejected somewhere in the 10-20 hour region.