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