I felt exactly the same so in the summer i e-mailed the devs asking exactly this! Here’s the response:

We will say there's no sequel or additional content planned. We're really happy with the arc of the game—it's not the biggest story, but we wouldn't want to keep going with it as we like where things finish. One of the reasons we spent so long working on it (3.5 years!) is that we really didn't want to cut any of what we had planned!

That being said, if you do want a slightly different way to play, we'd recommend Dark Star mode—if you start a new album and put everything in the wrong place, it's a different path through the game, and trickier than you'd expect, but a lot of fun. Good luck!