Thanks for playing my game and leaving such detailed feedback. I'll take note on the lack of a pause screen for future projects.
As you have surmised, the modular linkup system is where most of my time went throughout this jam, constantly iterating and tweaking until it felt good. So its really great to see it being appreciated.
As an interesting fact, the parts glowing when you get near them and not just when connected together was originally a bug. But since it added to the feel I kept it in.
As for the music, all I can say is I agree. I spent about an hour filtering through various royalty free tracks none feeling right for me. Then I found this one over on Soundcloud by Seth_Makes_Sounds and it just clicked. The best part is how the track evolves as it goes on, taking on a really chill and chipper feel as you get near the victory line. This was not timed on purpose but works so well.