I have to admit that I'm not entirely sure what mouse setting it's meant to change, but when I set "Invert Y axis" nothing seems to happen at all. I've only gotten as far as the tutorial in the game and I happen to be one of those crazy people that likes their camera with the Y axis inverted, but as far as I can tell I can't do that.
Viewing post in Voices of the Void 0.8.0 Bug Reports
Yep, pressing apply. I haven't tried it outside the tutorial, so it's possible it's a game mode thing, but it's also possible it's a me thing, which would make me sad because the game's freshly installed. As far as playing that way, I chalk it up to being a trackball user and growing up with airplane controls on most game cameras lol
EDIT: Tried it in story mode and no change there either.