There's a game called Soma which has a plot that largely revolves around this question. You play as a man who wakes up mysteriously in an underwater facility as

There's a game called Soma which has a plot that largely revolves around this question. You play as a man who wakes up mysteriously in an underwater facility as a circumstantial consequence of a "brain scan" you took 100 or so years ago. The "is it still me?" question pops up over and over throughout the game. It's incredibly thought provoking.