Last night, I set the game to 'Free' (rather than $0 Or Donate) to get re-indexed as per Itch.io's current policy. Look up the ongoing adult games on itch.io drama to know more. I'd rather more people have access to my games than be tossing me the occasional 5 bucks right now, ahahah.
It may also be that I updated the download's supported platforms, however: I neglected to do this back when I released/updated MERCANOID, and forgot to tag it as compatible with Windows, Mac and Linux.