Downstairs in Quinn's house, in the room with the round table, there is a black chest hidden in the rafters.
In the courtyard with the open fire, go down into the sewers. There's a necklace by a pile of bones.
Just past the above courtyard, there is an archer standing on a platform. Rope arrow up onto the platform opposite the one he stands on and slash the banner. There is a chest in there that is empty, but it registers as a secret.
There is a wall safe behind a tapestry in the back room on the second floor of the Tavern.
There is a ring underneath the elevator platform in the Guardhouse. (The elevator that is just inside the door that opens out onto the square by the Tavern.)
Climb up on the bunk in the back corner of the Guardhouse bunkroom and look for a small niche in the side of the ceiling beam. There is a purse in there, which counts as a secret.
In the Guardhouse kitchen, there are two open cupboards underneath the counter. Both have boxes in them. Move the boxes from the left one to find a lever. It opens a hidden compartment behind the boxes in the other open cupboard.
There is a purse down through the trap door of the Gallows, in the courtyard.
The next secrets can only be found on Hard and Expert:
In the secret passageway from the skull room to the Vault, there is a purse lying on the floor in the room with the zombies.
When you go down the elevator from the Guardhouse to the second section of town, you walk out through an archway. There is a chest sitting on the roof above the archway that should count as a secret, but it doesn’t register. Therefore you will only be able to get 10 out of the 11 secrets to show as being found on the Stats screen.
After you cross the bridge, open a door and enter the last section of town, turn right, walk behind the building and around it until you’re facing a wall to the west. Follow along the wall until you come to a street sloping downhill. Mantle up on the wall, just a little to the right of the street, then climb the steep, bluish roof. Walk down the other side of the roof, angling to the right. Don’t drop down into the courtyard, but walk across another roof to a flat rooftop. There’s a purse here that counts as the last secret.