1.

The code for the mailbox can be deduced with the help of certain objects found in the building lobby and throughout Fael's apartment.

2.

The greeting card, the lemonade recipe, and the piece of cedar contain useful information.

3.

Fael followed the instructions in the device's manual to the letter and used personal information for the secret code.

4.

If you know Fael's age, it is possible to deduce the secret code for the mailbox.

1.

The item found in the mailbox can be used in the apartment, on docks connected by cables.

2.

Upon solving a retro puzzle, energy will flow through the cables to power the next dock.

3.

If a cable disappears into a wall, it will inevitably come out on the opposite side of the wall.

4.

Once all 5 puzzles have been solved, the cable will power the electronic device at the front door.

1.

In the retro puzzles, tetrominoes (geometrical shapes made of 4 blocks) can be launched onto the grid.

2.

You can rotate the tetrominoes 90 degrees multiple times before launching them.

3.

The goal of these retro puzzles is to place the blocks onto "target" squares of the same color or type.

4.

Sometimes you'll have to use the puzzle walls, or other tetrominoes, to position or keep blocks on target squares.