Here is the full list of all 41 Labyrinth City: Pierre the Maze Detective achievements.
Lock yourself behind the door that leads nowhere.
Finish the The Forgotten City level with all its collectibles.
Throw the rock into the sea.
Finish the Haunted Manor level with all its collectibles.
Shock Dr Frankenstein's creature 5 times.
Finish the Village in the Forest level with all its collectibles.
Find out whether the chicken or the egg was first.
Change an option in the option menu.
Finish the Southern Castle level with all its collectibles.
Grow the magic bean.
Listen to everything he has to tell you.
Find Pierre's strange double.
Finish the Downtown level with all its collectibles.
Finish the Street Party level with all its collectibles.
Finish the Museum level with all its collectibles.
Get all the Achievements in game.
Catch Mr X... or not.
Finish the On the Docks level with all its collectibles.
Finish the Flea Market level with all its collectibles.
Finish the Final Giant Maze with all its collectibles.
Get all the Chests.
Get all the Pages from Mr X's Book.
Get all the Stars.
Get all the Trophies.
Get all the collectibles in game.
Find Gmlf in all the levels (apart from the Haunted Manor).
Find Coco in all levels (except at the Southern Castle).
Find Hoshi in all levels.
Find the Polar Bear in all levels.
Walk 10,000 steps.
Find the man who has seen the seabed maze.
Shoot both fireworks.
Lock yourself in the cage.
Search all the bushes in the Museum.
Get on the roof of a car.
Find where the pink animals come from.
Launch the real Golden Hen's rocket.
Find Pierre's twin sister.
Find Waldo.
Press M to "open map".
Catch 5 ducks.