Unlockable: Movie
First you must complete the game. After the screen that says "TOUCH HERE TO START" there is a blinking hexagon. Touch it then it will say "Play Movie?" press yes and watch the movie.
NOTE: To unlock the hidden preview video, simply get a high score on each mode (not the highest score, just a high score). After the third high score is in, you will see a "Play Movie" button on the touch screen. After watching the movie, it is accessed by tapping the new glowing dot on the title screen.