The Spectral levels are 3 different levels in Pac Man World 3.
The Spectral Cliffs
This is the first spectral level, where Pac Man is introduced to time keys, the Spectral Fiend, B- doings, and other items. Pac Man went to the top of the realm to rescue Pinky.
The Spectral Vale
This is the second spectral level, and is more difficult. Pac Man is introduced to blinker platforms, and more spectral ghost fights. Pac Man is also introduced to Clyde.
The Spectral Zenith
The last, and most difficult spectral level. Pac Man has to deal with many Spectrals. So does Clyde. On this level you are introduced to spectral energy lines and mirrors. Pac Man uses the path to get to Shadow Temple.