Every other page on this site gives you the answer. This one does not. Find your scene, read one line, and go back to the game — the link at the end of each nudge is the full solution if the nudge was not enough.
The three nudges that cover most of the game
Before you look up your specific scene, one of these three usually turns out to be the problem:
You are missing an item. Most puzzles silently refuse input until you are carrying the thing they want. They do not tell you this. Sweep the room before you re-attempt the puzzle.
Your actions are right, your order is wrong. Waking Aldous, serving tea and singing the lullaby all reject a correct set of actions performed out of sequence — and they fail silently, so it looks like the actions are wrong.
You are being too competent. A large share of the hidden achievements only fire when you do a chore badly on purpose.
Day 1
The driver will not take payment. You found one cup. There is a second one you have not picked up. → tin cups
The raven will not trade. It wants something you do not have yet, and getting it involves a razor. → porridge
Something is moving in the porridge and you cannot hit it. Stop hitting it. Take away its options first. → berries
The exercises are not working. The answer key is an object in the room, sitting on top of a piece of furniture. → exercise
The chandelier will not light. This is not a puzzle yet — you are short a candle, and it is behind a chore you have not finished. → chandelier
The cockroaches keep escaping. The corners are marked for a reason. → garden
The suitcase code from a guide does not work. It would not. Shake something that makes noise. → luggage code
The tea keeps getting refused. Two possibilities: your fill order, or the fact that the cat has not been dealt with yet. → tea service
The cup broke and you think you failed. You did not. Repair it and do the same thing again. → tea service
The wine cabinet needs a number you do not have. It is written in the room, on something belonging to a winery. → wine cabinet
The lullaby resets every time. It is a fixed eight-step order and it fails silently. → parlor
Day 2
The coffee scene finished but no achievement. Roasting was only half of it. → coffee
The feather is not working on William. You are aiming too low. → Day 2
The hunt keeps not counting. You have spare bullets and you think that is a margin. It is not. → perfect hunt
You got the key from the hole and left. The hammer was not for the hole. → pest control
Day 3
The alchemy boxes give no feedback. They do not react until the ninth click. → alchemy boxes
You finished the game and the last achievement did not fire. It does not start until after the credits, and it begins with a note. → "You've found him!"
When a nudge is not enough
Go straight to the puzzle index — one page per puzzle, answer at the top. If you only need a number, the codes page has every fixed lock in the game on one screen.