I've only just gotten around to trying it, and it still doesn't look like the issue's fixed. I have a Windows 10 computer, if that changes anything, since I know that's caused problems for games in the past. I took a screenshot of what happens when I go into windowed mode to see if that helps you at all. It wouldn't let me take one of what happens when I open the game in fullscreen mode, but for that the only problem is that the main menu is cut off at the bottom and sides of my screen.
Thanks so much for your help, I really appreciate it!