Walkthrough

I've bundled a walkthrough amongst other additional information into a digital booklet that you can get by purchasing the game. But I don't want to gate that information behind a paywall, so here's a plain text walkthrough as well:

Contains spoilers (obviously)

I'll give clues in increasingly spoiler-y order

Remember you can hold SPACE to show all clickable items on screen

Opening the safe

• There's a clue written on the painting
• You can't see it with the lights on
• You can't turn the lights off, because the duck will kill you
• You need to take out the duck
• There's some useful items around you can use
• You can get a stick of TNT from the kitchen
• You have to get another item to get the TNT
• Searching the living room will get you the right item
• Find the coin in the sofa and use it with the gumball machine
• You can light the TNT with a candle
• The candle is on the table in the living room
• The duck isn't stupid, it knows you're trying to blow it up with an obvious stick of TNT
• You need to disguise it
• There's something else in the kitchen you can disguise it with
• Combine the lit TNT with the bread
• Give it to the duck
• Now you can turn the lights off and view the painting for the safe code

Getting the knife

• Something useful is in the safe to help you with this
• Is there some way you can get the duck to let go of the knife?
• Maybe if it wasn't watching you
• Use the glue on the duck's eye (the duck in the portrait, that is)
• You can now take the knife

Leaving the building

• The code for the padlock must be written down somewhere
• It's hidden behind something
• You need to use a tool to reveal it
• There's a pool of candle wax on the table in the living room
• Use the knife with the candle wax to reveal the code for the padlock
• If you try and go outside, the duck outside will kill you
• You need to 'deal' with the duck first
• Stab it in the eye, now you can leave safely

"Secret" Ending

• If you persistently try and feed the ducks bread or give them money, you will see a super secret game over screen