Its going to sound dumb, but couldn't get the game to start and wondered if it was broken as the main menu doesn't start the game with S/down. Moving to a different scene does let you start.
It's probably less you being dumb, and more me designing a not entirely intuitive interface. I thought I'd be clever by including the title screen in the scrollable menu, but it may it have been better just to do a standard "Press S to start" style title screen.