How do you open the door on Mythology Island?

Answer 1

There are at least five doors on the island.

The Minotaur Door

Use the reed pipe (Flute) to play the 8 notes that correspond to the colors on the circle, which are blue-blue-green-yellow-yellow-red-blue-green. You get the reed pipe from the Grove of Temples, by going into the Temple of the Muses.

Poseidon Realm Door

Place the starfish on the altar (from Poseidon statue in museum)

Hades Realm Door

Place the pomegranates on the altar (from the tree in the Garden of the Sphinx)

Poseidon Throne Door

Hades Throne Door

Olympus Gate

Opened by Hercules (when Zeus has Sacred Items)

Answer 2

To enter the Minotaur Lair, use the reed pipe from the Temple of Apollo to play the 8 colored musical notes: blue-blue-green-yellow-yellow-red-blue-green.

To enter the realms of Hades and Poseidon, you have to make an offering on the altar. For Hades, it is pomegranates from the tree in the Garden of the Sphinx. For Poseidon, it is the starfish from his statue in the museum.

You cannot move the rocks from the throne room entrances until you have Hercules to help you. Return all 5 sacred items to the Tree of Immortality to solve the inscriptions. When Zeus has the items, Hercules will help you -- you need the Touchscreen Mirror from Aphrodite's test.