Here is the full list of all 24 Oracle achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Swords and Skulls.
Visit the ruins.
Explore the corn field.
Explore the wrecked coal mine.
Find the old outpost by the river.
Explore the wooden windmills.
Find the grave of the Fallen.
Explore the maze.
Find the Gorge.
Explore the Radio Station.
Explore the mine that goes on top of the mountain.
Explore the boats by the shore.
Remember her neck tattoo.
Visit the Tower.
Find the hidden passage.
Magic under the Roar.
Visit the railroad and the train wreck.
Cross the wooden bridge.
Red tree inside the Pit?
Walk under the waterfall.
Explore the Graveyard.
Explore the Church.
Explore the tombstones.
Wake up on the Island.