Grimrock

I wanted to play the game in windowed mode. So I switched it over but now I can see some of the screen and can't hit apply under the options menu. I play the game through Steam. I've tried using alt+enter and even set the launch option to -fullscreen. Nothing seems to work and I can't play the game. I'm not sure what to do.

This happens when the height of your window / desktop is less then 800. Since it seems your full screen resolution can be larger you got two options:
1) temporarily increase the resolution of your desktop so you can reach the "Apply" button.
2) open the game's config folder located inside your user's profile: documents -> Almost Human -> Legend of Grimrock 2
there open the game's config file grimrock.cfg in a text editor, find the line "displayMode = <number>" and replace whatever number is shown there with "1". Save the config file, then start the game and you should be back in fullscreen mode.

That worked. Thank you so much!