Guess the combination to Oscar's safe before finding the code.
Open the secret bookshelf in the guest room from the outside.
Returned Christmas Duck to his rightful place.
Turn on every faucet in the house at once.
Completed the game in less than 1 minute with no Modifiers enabled. (From New Game in a single session only)
Activated all Commentary Nodes with the Developer Commentary Modifier enabled.
Completed the game.
Completed the game having found all 23 of Sam's journal entries.
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)
Found Mitten's secret diary.