Oh, I have no knowledge of how the Itch app works. Care to explain the fix? I probably won't fix it for v0.1.x, but I might be able to do it for v0.2.0.
Viewing post in Super Mario 63 Redux [Tiny Demo] comments
No problem.
The Itch app manages game installations and updates, but if the game executable is not executable on the current architecture, the app refuses to install (or update) the game.
So, before you make the ZIP package, you need to set the file executable flag, only after that, you can put it in the ZIP file.
This is precisely the chmod +x redux.x86_64 you mention, but before zipping the package.