I'm sorry about the issue. So, I can only explain what happens on my end. I basically upload the game folder to Itch using Butler. That system handles all the rest so I am not sure how it packages/zips files. I have no control over that as afar as I am aware. If you want I'll be happy to send over a Steam Key for the game and see if that resolves your issue. Email me at stardropgame@gmail.com and I'll try to help you out there.
As for MAC versions, I do not have anything to debug / test the game on so I am surely not confident in trying to make builds. I'm really sorry about that. If I had the funding I'd outsource it but it's not an easy task and I wouldn't have control over any kinds of bugs that might creep into the game due to the porting.