Thank you for your feedback! The puzzle does have a bug which I think I've fixed. I will release the update this week. It also includes an object respawn in case something falls (or is thrown) out of the play area.
As for your request on the expansion parts only - thank you it's a great idea - I plan to include a "reset+" option in the future which will jump to the expansion content. But I'm focusing on getting the PC version out next, so this is still a few months away.