Gone Home
Completed the game.

Letters to Katie
Completed the game having found all 23 of Sam's journal entries.

Meow Meow Meow
Found Mitten's secret diary.

Homerunner
Completed the game in less than 1 minute with no Modifiers enabled. (From New Game in a single session only)

Speedreader
Completed the game having found all 24 journal entries, with no Modifiers enabled, in less than 10 minutes. (From New Game in a single session only)

Behind the Scenes
Activated all Commentary Nodes with the Developer Commentary Modifier enabled.

Nesting Instinct
Returned Christmas Duck to his rightful place.

Wet Bandit
Turn on every faucet in the house at once.

Intuitive
Guess the combination to Oscar's safe before finding the code.

This Old House
Open the secret bookshelf in the guest room from the outside.