Play the "Library Memory" level. Get through the maze to reach an office room with two cubes on the table. Choose the red cube.
Avoid the patrolling stewardess hiding in the seats. Hide in a row that has broken lights or she will see you.
You will start on an island at the beginning of the game. After learning how to progress, you will end up in the forest. Move forward until you find the axe. Use it to chop up the trees that are in your path. Ones that you can interact with have a blue aura. Also collect the gold duck when you find it. Continue and you will have to move some mine carts and chop more wood to progress. You will eventually go up a mountain and find a pedestal. Place the golden duck there and practice what you learned on the island to move to the next map. Continue forward, press the button, move across the bridge, and reach the briefing room. Watch the video, then look through door to the left to open a hallway. Use your running skills to proceed to the front door. Walk on up to the reception desk to find a blue duck. Approach it and a hand icon will appear. Interact with it repeatedly to advance through the pages.
Complete the true final Boss section with at least 31 seconds on the clock.
Play the "Childhood Memory" level. Once in the mirror universe, you will find two dollhouses sitting beside each other in front of you. The dollhouse on the left has stairs. Climb the stairs to reach the third floor. Look towards the other dollhouse. Make a running jump across to the other dollhouse's third floor (on the PC version, press [Shift] + W to run, then [Space] to jump). If a new scene does not start, turn around and move towards the wardrobe near the bed.