Before I say anything, this wont be a Spoiler-free topic
So, there is always a game, movie or a series that blows your mind away with it’s ending. Sure, there are epic endings - but this topic aims to cut deeper, I expect nothing less than ending that makes one think. One of my favorite games, called the Darkest Dungeon ends amazingly. Basically, at the very end - the only thing you achieved is… well nothing, see for yourself.
It ends with this:
https://www.youtube.com/watch?v=slBUGumPc4s
I especially like the parallel with the beginning. You start out as a family member, begged by your ancestor to rid their mansion of the horrors that they unleashed before committing suicide- the very same happens in the end, instead you would be the Ancestor and another person is to take your place as the reclaimer of the family heritage - only to meet the same fate.