Clear every song in the Survival Mode. Then when you highlight Survival Mode, press Select again for Hyper Survival, where the speed is increased.
Karankoron no Uta
In Arcade mode, play two songs from 1970 for the first two stages. The song will unlock as a Third stage selection.
Reversal, Passing and 'Half and Half' Modes
After playing and recording a high score for all 20 tracks, press Select during any song's loading screen in Free mode, to toggle between three options which change the direction of the Pop'n Music symbols. Great if you prefer the notes going from the bottom of the screen to the top like in DDR.
Suki Suki Song
In Arcade mode, play two songs from 1960 for the first two stages. The song will unlock as a Third stage selection.
Survival Mode
After playing and recording a high score for all 20 tracks, press Select when highlighting 'Normal' mode in Arcade.