I'm so happy you've enjoed the game :)
"(though I realise that would've been clear if not for a last export bug)"
Yes. Who would have thought that uploading untested code with 30 seconds on the clock is a bad idea... (Jokes aside it taught me a huge lesson and made me reconsider some parts of my gamedev workflow/approaches)
"the puzzles felt challenging and I felt clever doing them, while never feeling frustrating either"
I've actually never designed any puzzle levels before, so I've decided to make puzzles with multiple solutions + give 1-2 more reverses near the last 2-3 levels.
" like you did for the final moment returning the Orb of Reversal."
Yeah! I was also surprised how it turned out. For this scene: Artist drew a pedestal --> Musician made a choir --> Sfx designer made a sound, which is played after placing the Orb (he also suggested that player should place the Orb on the pedestal) --> I've put it all together