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.
Find the Gorge.
Red tree inside the Pit?
Explore the wooden windmills.
Walk under the waterfall.
Explore the Graveyard.
Cross the wooden bridge.
Visit the railroad and the train wreck.
Magic under the Roar.
Find the hidden passage.
Remember her neck tattoo.
Visit the Tower.
Explore the boats by the shore.
Explore the mine that goes on top of the mountain.
Find the grave of the Fallen.
Explore the maze.
Explore the Radio Station.
Find the old outpost by the river.
Visit the ruins.
Explore the wrecked coal mine.
Swords and Skulls.
Explore the Church.
Explore the tombstones.
Wake up on the Island.