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