Contacted support, but apparently you have to go discuss your refund with the developer, ridiculous. Of course the developer says he did nothing wrong and all is very clear in the description, that you only get the soundtrack and not the game.
I'm not the only one misleaded by this, by the way, another person complained about it too on the game's page. If you use steam enhanced or the website isthereanydeal, you get informed of this "sale". The game is even listed on itch io game sales page.
It's not about the two bucks, it't about the principle.