
Lol, yeah. I’ve done a few playthrough with some friends and one regularly walked into the fire. Always a good laugh!
There are some storyline things above ground, namely the Crater and sailboat. Those all come along via exploration, but most is underground.
What I really liked is that there’s no character exposition or beating you over the head with the story. It feeds you information slowly, sometimes disjointed. Not until the end does it make it clear what’s going on, so there’s a lot of incentive to find the next piece of story line to see if you were right in what you thought was going on.

This was one of my favorite games. It has 2 layers to keep you interested. The survival is fun, but it’s not primarily a base builder but a plotline game. You utilize your base to maintain supplies before you venture underground into caves to further the story line. Depending on how you play, half of the game or more will be in the caves progressing the story.
No, they did not. I picked it up again a few months ago after playing it for a while years ago. Stopped playing it after a few days of intermittently opening it because the algorithm constantly raided me and moving the dwellers around to properly defend was still a nightmare. Stopped being fun real quick so I remembered why I quit originally, and quit again.