Here is the full list of all 22 Dreaming Sarah achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Finish the game.
Find the watch.
Help the pianist.
Discover the ancient aliens.
Shrink the eye.
Find the bullet.
Find the juice box.
Find the heart-shaped key.
Find the dead cat.
Find the paint bucket.
Find the magnifying glass.
Find the pill.
Find the ID card.
Find the glasses.
Find the compass.
Find the bus card.
Find the shell necklace.
Touch the moon bunny.
Find Blockhead.
Find the hat.
Find the bag of seeds.
Find the umbrella.