@PolarisInParis The keyboard controls are Z to confirm and X to back, are you sure you were hitting Z? I can't see a reason why keyboard controls wouldn't be working... only other suggestions are to make sure that the window has focus obviously or try with a gamepad. What OS are you running by chance?
edit: Wait you obviously got to the intro so it's not like the controls aren't working. Make sure you're using Z. If it's still not working it'd sure be nice to know why.