https://bugs.winehq.org/show_bug.cgi?id=38182
--- Comment #3 from Andrew Eikum aeikum@codeweavers.com --- Sagawa: Yes, you're right. And on Windows, the in-game slider also affects the volume level in the Windows mixer.
We chose not to allow Windows applications to affect the system volume slider, so this is expected behavior. We could do some internal volume control to emulate this, but I really don't want to give Windows applications control over the final, end-user volume levels.