https://www.pcgamer.com/games/survival-crafting/after-3878-days-in-early-access-zombie-survival-game-7-days-to-die-finally-releases/
Significantly more than seven days to develop.
It's actually come a long way since it first became available. I remember playing 10 years ago and some animals like deer didn't have walking animations and would hop around the map
I only picked it up recently and I have put in 230+ hours (granted, some on stream) but I think it is one of the most fun survival games out there for me and a great zombie themed game overall.
I really appreciate the inventory handling, that there are no bosses and just zombies to deal with. My only gripe is - as with many of these games - that there isn't a real end to a playthrough. But such is the nature of a sandbox.
Absolutely not worth the full price tag, but on sale it's an easy recommendation from me.
A group of friends and I played a few years back and we found the natural end was when we could survive the hardest of the blood moons in our base without having any damages or breakthroughs and could easily beat any of the areas that were supply runs. We also had built multiple vehicles so we would bomb through in a convoy to wherever we were going and clear everything.
That was the end because we didn't want to play anymore.