The only hitch is that after the procedure is finished, the client's mind won't be able to accept the new memories with the old and will die, so it's only done on terminally ill patients. Once the procedure is done and they've relived their life, it's the last thing they'll ever do.
The gameplay isn't much to speak of, there are a few easy flip puzzles but other than that you're just going through a 16-bit looking RPG that's almost entirely reading dialogue. The dialogue is quite good imo, and the story and music is heartwrenching. I don't think something's hit me like this since watching the movie Up.