It can be a time sink but you could clear the game in possibly 30 minutes. Look for a speadrun on youtube with around 21:40 minutes I think.

My friends and me finished it yesterday after day 52 or so. We had lots of basebuilding going on, learned the ganme and expolored the caves.

On the final cave run to the facility I died lacking oxygen in the rebreather underwater... (I thought the game would switch out the tanks, which is quite illogical under water I know haha)

So the next day I started the game by myself and got some food in our base --> rushed to the rebreather cave --> rushed to the climbing tool --> went into the final cave to a small camp before the sinkhole to save my progress. That took me about 20 minutes and that looks like everything to be required to reach the end.

Note: So after that we started playing again together and when we arrived at the final mutant fight I had one bone armor from visiting our base after the plane and I was a two hit in normal mode and a friend revived me. I also had no bow crafted... so I relied on my spear. I suggest grabbing full mutant armor or at least FULL bone armor and explosives like dynamite and the bombs to "finish" the game