Thank you for letting me know, that is very helpful. Last patch was all about improving controls so something might have come undone. Unfortunately I’m away on vacation and won’t have access to my computer until mid next week, but here are a couple of steps that might help you get past the main screen in the mean time:
If your mouse appears on screen and you hover over the options, do they get hilighted? If not try switching from using keyboard to mouse and back until the UI focuses on one of the elements.
If you have a controller, plug it in before starting the game and move the joystick. It should automatically snap to the single player option for you to click. If that doesn’t work try switching between the mouse and joystick. One of them hopefully will be able to focus on one of the buttons.
Sorry for the inconvenience, I’ll try to patch it soon!