Concept:
Action adventure puzzler.
Usurper seizes the planet's aristocracy during the Grand Masquerade Ball, enslaving all attendees with the enigmatic Masks.
Your enslavement doesn't go as planned, and you retain your will, but lose your self.
Taking advantage of your immunity from the enslaving power of the Masks you use each type of Mask's special abilities to fight the Usurper's enslaved minions and free your planet.
Wearing a Mask you take on that Mask's form and abilities, becoming non-threatening to slaves of that Mask type.
The Pearl Mask gives you the form of the Pearl Faces, the cannon fodder of the Mask slaves (allowing you to pass them without them attacking you).
On contact with a Shadow Mask you are transformed into a ethereal form that allows you to pass through obstacles, but you are unable to interact with your surroundings until you "remove" the Shadow Mask by touching a Shadow Mask again and return to your prior state (works like a slow teleport between Shadow Masks, and useful for reconnaissance).

Using ptoing's C64 palette.

Note: tiles were tweaked some for more efficient tiling but I was to lazy to update the mockup.