I loved the ending, just take a step back and look at what you had to do. (SPOILERS AHEAD!!!)
You helped people move on from a place where only a small piece of themselves could interact with the world. They used what little connection they had to explore every inch and option possible in their world, leaving them trapped in a "dead" world. The music reflects the scene; Beautiful songs with a steady beat, but eventually they become endlessly repetitive. After a while, the music seems tragic, the steady beat has been the same for minutes, hours, and what was once beautiful begins to dull. But then you find another piece of the world, and another, and the track changes, and the game seems beautiful again. But it's that same, steady beat. You are trapped in a finite world yourself, you know, exploring the world with just a character you move around on your screen with arrow keys to represent all that you really are. After helping 3 others leave this world to find the next, it should be a simple task to help yourself... But instead, you wander hallways, you look in the paintings and old, fully explored worlds again... when all you had to do is simply move on to the next room over. There were no directions to tell you to go there, but it's such a simple and obvious path. You trapped yourself in a simple world, listening to the same beat, over and over. Maybe you left the game and returned, but your character was still stuck in the same place. Only when you moved on were you able to beat the game. Congratulations you beat the game, there's nothing left of the game to explore except your own memories. How long will those last until your mortal life ends, or your finite memory betrays you? It doesn't matter, it's something beautiful that you fought and won for, and it's yours to treasure until it's time to move on yourself. Or at least, that's how I interpreted the ending.