1440x1080 the resolution I played at is now missing. The only 4:3 resolution I see now is the original 800x600. I have a suspicion this has something to do with trying to address the bug of resolutions resetting upon restarting the game. Personally I had to set my resolution back every time the game booted up and encountered freezing, which was most of the time.
EDIT: Nevermind this is an issue on my side that correlates to a Windows update. Apparently 1440x1080 is not a default option and was one of my custom resolutions that was removed on the last Windows update.