I enjoyed it, it was sort of pointless but a fun watch. I thought it felt interestingly "video gamey" from the start, I honestly have to wonder if there's a "Fallout" fan in the writing team. The little level 1 main character ventures out of his vault on a quest, and "levels up" along the way getting stronger with each big encounter. He even finds Dogmeat
.
There were also some (very?) heavy influences "Zombieland" (the first one) in there.
As for the lack of seeing many monsters... I'd put that down to it being a Netflix produced movie. They don't have the CGI budget of a full on blockbuster.
And the lack of gore I guess is just because it's a 12 and being aimed at families and teens IMO.