

What’s the license? dual-licensed: GPL version 2 or later and CC-BY-SA?
I’d say you’re asking the wrong group of people for permission. You should be asking the people mentioned in the AUTHORS file. Or maybe just inform them, because I think generally you’re right. Seems they specifically licensed it CC-BY-SA. So you need to attribute. But they gifted it to you, including for commercial purposes.
And maybe you give something to them. Like a free key for your game?!
Sorry, I don’t want to come off wrong here… But it’s 2026 and I think everyone should have access to a Linux box these days. All you need is a thumbdrive and a few gigabytes of free memory and you can dual-boot. Takes one or two hours of your day and you’re set. It’s always a bit difficult to maintain releases and not have the hard- or software to test them.
Seems github has some hiccups right now so I can’t check what kind of toolkit you’re using… But generally speaking, Linux is awesome for developers as well. (Edit: It’s Unity)