So a lot of times in games and movies, songs are written with the specific notion that they will flow seamlessly between each other. Mass Effect did this a lot. Baldur's Gate did it at certain points. Lord of the Rings is another great example of a recurring theme. These songs, while different, are in the same key/notation/pitch/tempo. It adds dramatic effect and allows a recurring theme to be used.
The hard mode instance idle music:
https://www.youtube.com/watch?v=PjbJ0IjWpJ4
...And battle music:
https://www.youtube.com/watch?v=_zEkOIgjdko
... is another example.
I don't know why, but I never considered songs like these to be "complete" when they are kept separate. So I overlaid them on top of each other. If you want to hear them together, here it is.
https://www.youtube.com/watch?v=LRm8bNgG...e=youtu.be
The hard mode instance idle music:
https://www.youtube.com/watch?v=PjbJ0IjWpJ4
...And battle music:
https://www.youtube.com/watch?v=_zEkOIgjdko
... is another example.
I don't know why, but I never considered songs like these to be "complete" when they are kept separate. So I overlaid them on top of each other. If you want to hear them together, here it is.
https://www.youtube.com/watch?v=LRm8bNgG...e=youtu.be