If you bought the game more than 90 days ago you can't. If you purchased it recently, you're still out of luck I think since he's pretty much been bullied to not care anymore.
Instead of giving everyone refunds. The more logical response would have just to been to update the itch.io version no? That way he can essentially give everyone the new game without having to dish out refunds or receive hate? Odd decision making on his part.
