I downloaded the game and opened the zip, the main file was named saga.x86_64, I renamed it to saga.exe and it worked. I think that the itch launcher starts the UnityCrashHandler64.exe instead.

The game worked! the mouse sense was extremely high, I have noticed that this can be different from linux to windows. But the gamepad controls worked fine!

Although I would have preferred a twinstick aiming method instead of moving the courser around on the screen.