You must start the game on the easiest level. So DON'T press 'J' or 'K' before pressing FIRE to start the game. You can easily see if its the easiest level you start on, as there's only one skull on the first screen. Starting play on a harder difficulty will get the recording DQ'ed.
IMPORTANT: We only play 3 loops, meaning the third time you get to Montezuma's Treasure room and complete it, that's the score that counts. All points gained after that is worthless :)