Beat a level in puzzle mode. Then, hold R2 after the professor falls to make him walk faster.
Stage select
Choose "Puzzle Mode" and select the "Password" option. Press [Down(2), Right, Up(2), Right, Up(3), Right] two times, then press X. The color of the block should be Light Blue, Pink, Green, Light Blue, Pink, Green. A stage select option will appear when the game begins.