My screen 1920 x 1080, so its slightly higher than the current max the game offers, it's not a huge deal when you can full screen it with alt-enter, but i'd like it to be the default for my screen.

Hey again. Good question. Here's what's happening now: 

• full screen should use the full monitor resolution regardless of aspect ratio
• windowed will use 16x9 aspect ratios and only support certain ones (I'll list them below for the curious) with the max being LESS THAN the full screen size. 

This, of course, assumes you want the window to be smaller than the screen, but I see your point that you might want to just fill one monitor in a multi screen setup and be able to use the others which full screen prevents. This would be an easy change and I can add it into the next build for you!

Supported windowed sizes:

1024 x 576
1152 x 648
1280 x 720 (720p)
1366 x 768
1600 x 900
1920 x 1080 (1080p)
2560 x 1440
3840 x 2160 (4K)

Supporting only 16x9 in windowed is purely because our main UI for the missions works best in that aspect ratio.

Actually i use a single monitor, i just like it to be full screen when i play lol, nothing too crazy XD