oh don't get me wrong, I rated this game pretty high, its not far from perfection ;) you don't need to change the song entirely, you could add some soft spooky pads to make it just dark enough to fit the them of the game. a good key for pause in my opinion is "Esc" or "Enter", I say this because "space" is usually used for actions such as fire in games from this genre. I'm myself a music producer originally so I absolutly salute you for producing your own track for your own game! :)