So in my recent PB I found out there's not just a 2nd quest but the game does infact play on an infinite loop - what's more the dugeon layout of subsequent quests appears to be identical to the first quest dungeon layouts as far as I can tell, right down to the items given - however someone in my chat was saying there's a special icon mark that gets given to you after you max out your high score with a count of 9999 as a kind of easter egg.

I remember seeing on @LiteralGrill 's Any% guide document that there was a community interest in routing 100% but there doesn't appear to be any actual changes aside from the high score easter egg beyond the 1st Quest. I suppose there's potential for some kind of max score category tho? ...I mean, I'd gladly do some attempts of something like that but I imagine it'd be awhile until someone masochistic enough to join me turns up y'know xD