Here is the full list of all 24 Cleo - a pirate's tale achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Fall down the stairs of the lighthouse twice
Do not dare to go into the dark
Pick all Folo flowers on the island
Bring exactly 20 flowers to the siren
Win your very first game of Kraken Fodder
Don't give up until you win your first round of Kraken Fodder
Solve the finger puzzle in just two steps
Try to take a fish after Herbert left
Play Cabeca's leitmotif on the kalimba
Cut off all tufts of grass
Win against Fleur on the very first try
Go fishing 25 times
Go fishing 50 times
Go fishing 100 times
Visit every place of the McIanlly Palms map
Read a messages in a bottle
Read 10 different messages in a bottle
Read 25 different messages in a bottle
Complete the Coffee to Know Meditation flawlessly
Suffer more than 20 electric shocks
Win all Kraken Fodder games on the first try
Defeat Erik, Fleur and Schmodor in Kraken Fodder
Thank you for playing "Cleo - a pirate's tale"!
Find all 64 messages in bottles