The Code Breaker achievement or trophy in Twin Mirror is a secret one that you can unlock. Unlike most secret achievements or trophies in Dontnod’s mystery thriller, you can earn this one regardless of which branching narrative options you’ve picked. It’s a permanent fixture in the story, but you need to uncover clues and deduce the correct code to unlock it.
There are story spoilers for Twin Mirror from this point. If you aren’t past the midway point of the game yet, don’t read past the image below.
As Sam, you will visit Nick’s fishing shack as you investigate the events behind his murder. After a tense conversation with Joan, you can explore and find clues to work out what report he was working on, which got him killed. If you head back to the entrance, you will see a fishing bag under a bed. Grab it and place it on the table.
There is a lock on the bag, and you need a five-digit code to open it. The Code Breaker achievement requires you to break into Nick’s fishing bag on your first try. To do so, you have to discover vital clues around the shack to work out the right code. If you mess up on your first try, you can’t unlock the achievement or trophy, so use these steps to help you.
Head to the locker on the back right wall. You need a key to open it. Head back to the table with the bag on it, and look at the fish painting to your left. Inspect it to get the locker key. Open the locker and rummage through its contents. Make sure you grab the note on the right side of the locker. It has four colored dots on it with corresponding arrows and the word caterpillar. Remember these for the next step.
Walkabout towards the table and look left again. You will see some of Nick’s photographs stuck to the wall. Inspect them, and look for Joan’s caterpillar drawing. The caterpillar has colored dots that match Nick’s note. The caterpillar’s segment colors are — from left to right — red, green, blue, red, and yellow.
Go over to the table and put your evidence down. Look at Nick’s note again. The colored dots’ arrows point in different directions on the lock. Using the note and Joan’s caterpillar drawing, the lock combination is Right, Down, Left, Right, and Up. Move your thumbstick and hover over the lock. Inspect it and use your controller’s buttons to put in the correct code. If done correctly on your first try, the achievement or trophy will pop.