Thank you for telling me! Looks like hitting Continue when not having a save is causing an issue. I'll fix it in a few hours! If you hit "NEW GAME" it'll work normally.
As for the buttons not working on the title menu - make sure your mouse isn't on top of CONTINUE on the title screen. That'll prevent you from using arrow keys/controller joystick. Alternatively, you can navigate the title menu with the mouse.
When you hit NEW GAME it'll ask if you want to use Mouse Controls (or you can change it in OPTIONS).
If that's not it, I am unsure what's going on.
(Edit: CONTINUE GAME when having no save now works)