That's odd. It should work. Are you using the itch client or are you downloading it directly? Where do you get the message that your PC isn't compatible?
Viewing post in Unsung Warriors - Prologue comments
Not really clear to me what the error is. Can you send a screenshot via mail (http://www.unsungwarriors.nl/contact.php)? You can also try to download the game directly from the itch.io, website, to see if that mitigates the problem.