LemonheadVGM

This might be late, but something I would do is add more energy to the song to convey the type of feeling the boss conveys. If you want a frantic theme or an energetic theme, increase the tempo/pulse and re-harmonize it accordingly. If you want a menacing or ominous theme, slowing the track down and adding a more spaced out pulse should do the trick. I hope this helps at least a little bit.