@matt1211, yep, you can disable the music under settings. Also note the "impatient mode" option for speeding up battles.
I'm still not seeing new options and have got to chapter 3 (though I didn't take the time finishing all the endless dungeons this time, since after I completed the first one and didn't really get anything I didn't see the point in grinding all those upgrades).
I believe though, the problem was that while I completed the game back in march of this year,the game wasn't actually finished until May, or at least there is a comment from the developer on the Itch.io page saying as much.
I also simply restarted from the "view credits" option, and didn't look around my old save in chapter 3 or speak to remaladin either.
So I am hoping options to activate new game plus and collectable features will show up somewhere in chapter 3, though since chapter 3 is a lot of fun anyway, almost an entirely different game from chapters 1 and 2, I certainly don't mind playing it again.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)