Here is the full list of all 31 The Dark Eye: Memoria achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Adjust the horns towards the spheres.
Make your decision.
Complete Chapter Eight.
Complete Chapter Seven.
Complete Chapter Six.
Complete Chapter Five.
Find the Caverns of Fail.
Collect all elementals.
Persuade the spirit of air to help you straight away.
Throw all items into the chasm.
Give all items to Xerxes.
Complete Chapter Four.
Stone, dust, stone, dust.
Complete Chapter Three.
Ashes to ashes, stone to dust.
Defeat the spider.
The forest is my home.
Find the fox within the labyrinth.
Complete Chapter Two.
Catch the rabbit at the first try.
Give Bryda the wrong astral accumulator.
Tread lightly.
Shards crack loudly.
Do you have the guts to start an argument?
Find out who of the adventuring party lies at the first try.
Turn the pig on the grill.
Does Bryda know who you really are?
Complete Chapter One.
Try to tear down the wall with the golem.
Do You Like Riddles?