this is just a repeat of a very old game I used to play. But it did remind me how much I enjoyed it, so thanks!

Good build up of parts, perhaps some deep timpani/tom/drum things could help give an underlying beat, and can imagine some female vocals...
Overall really like it, laid back, could make it loopable nearly :)

Hi Jim,
My backgrounds from an overall arrangement POV, hope it'll be useful!
At first I thought it was a bit busy, but there's great sections where it pulls back to just drums, bass, synth lines, great build up between sections, it could be improved by pulling back eeeven more? A well placed silence would be epic in this, before a blast. Sort of like the boss has just burst in.
Though the loop is a good starting point, you could try to have two distinct chord structures/riffs to go over the same underlying bass line? Then structure like A-B-C-B-A or something.
Overall I really liked it, really tense which is the best thing for a boss battle!

I like the feel of the piece, I'd have liked a bit more of a distinctive melody but thats just my opinion, and being for a video game doesn't really matter as much. Something you could very easily do is rework the end so it loops into the beginning?