if you mean the itch.io play button (the orange 'Run game' button that loads the game), i have no real idea how to help. sorry!
if you mean you can't push the play button on the main menu, this is because it's not actually a button. instead, it requires you to type.
the main menu requires you to type the letters 'type this to play' in order to begin the game.
you also may need to click the game so that it has keyboard focus.