There's only borderless and fullscreen. Which I think is fine for the time being, but I would highly suggest adding a borderless windowed mode, if possible.
Now, my actual problem is with windowed mode, as most resolution options are greyed out for some reason, and you can't put a custom resolution, which is also a problem because for some reason my resolution is not listed, even among the greyed out options.
It's a bummer, because I wouldn't have an issue playing windowed mode to alt+tab easily if it at least let me choose the correct resolution. As it stands, I have to either commit to fullscreen or have a smaller window than my monitor, neither being ideal.
Also, I had an issue with the audio cutting out during gameplay, but coming back for the menus and only the menus. Basically, when paused, audio worked. When un-paused, it cut away
Edit: Typo in the title