Bikini Girl
If you complete the first 10 rounds of the game in under 20 seconds each and get a perfect score in each bonus round, you should then have over 240,000 points. After you get this feat, you will then see a window at the lower left corner of the screen with a girl in a bikini.
Level Select
Start a new game, and then hold UP + (A) + (C) + START. When the "Round 1" screen appears, release all the buttons. Now you can press UP or DOWN to choose the round that you start on (up to 36).
