Complete the game on the Hard setting to unlock the Frame Skip option, which you can turn on or off. Once on, it disables the game's slowdown function.
Hard Mode
Beat game on normal to unlock hard mode.
Insane Turbo Mode
Beat the game on Hard Mode in order to unlock the Game Speed option. You can set it to ''Turbo'', in which case the game will move twice as fast as normal.
Music Test
Beat the game on Easy difficulty to unlock a Music Test option under the Configuration menu.
Subtitles
Beat the game on Normal difficulty, the option to turn on or off the Japanese subtitles during the movie sequences will now be unlocked.