Most players should find the Moreau Labyrinth Puzzle long before they find the Mermaid Ball that they need in order to solve it. The Puzzle can be found at the start of Moreau’s area, right beside the windmill. To get the Mermaid Ball and solve the labyrinth, players will first need to finish Moreau’s area and take him out in a boss fight.
After the fight, players will find themselves back at the start of Moreau’s area where they entered the first Windmill, and they will be back beside a locked gate with some yellow paint scrawled on it. Use the crank to open this gate, then move on up the footpath beyond it.
As they travel up the footpath, players will notice a small wooden hutch on the left side, across a wooden footbridge. This will contain the Mermaid Ball. Players can grab it then, then explore the rest of the area where they will find a new handgun, some ammo, and some flashbangs in the well. Afte that, they can return to the labyrinth to place the Mermaid Ball inside and solve it.
It’s an easy enough route, with only one part the might cause some issues but players will be able to clearly see where that is.