I just got the game and downloaded it on Linux Mint and I can't get it to be in full-screen. there's no maximise button on the top right of the window and I can't see if there is a fullscreen toggle in the settings of the pause menu because for some reason I can't navigate the settings menu with my keyboard (is that normal?)
I have attached a screenshot of how the game appears on my screen

I'm still fairly new to Linux overall and still have lots of trouble with things that don't seem to be well documented online. I know on Windows 10 you can usually press ALT>ENTER to make a game go into fullscreen borderless mode but that doesn't work and I can't find any information about this online. I will be extremely thankful if anyone can help me put the game into fullscreen.


Edit: I figured out that by going to the displaysettings.ini file in the games folder "/home/user/GOG Games/Psychonauts/game/displaysettings.ini" I can set fullscreen to "true". But when I went into the game, it still wasn't in fullscreen. after trying to mess around with the displaysettings file, I realised that I CAN use the mouse to navigate the settings in game after-all, but the reason I didn't figure this out before is because the game seems to think that I'm in fullscreen when I'm not (even if the fullscreen setting in the ini file is set to "false") and so I have to move the mouse into some really weird spots on the screen for it to highlight an option rather than hovering directly over the option like you should expect a game to work. When I eventually found the spot of the screen to click on the graphics settings, I found the ingame fullscreen option that actually worked this time. So I figured that out. But now a new problem arised: when I exit the game, the resolution I set in the graphics settings carry over to the entire computers display settings and I have to manually change my desktops resolution back to 1080p every single time.