Find and feed three spiders during the game to unlock this achievement.
Kill the captain of the gate watch in the game in order to achieve this. Get the urine sample in the locked room right next to yours when you begin the game, buy the syringe from the nurse downstairs, combine the two and inject the captain with it when he's unconscious.
Buy the two pieces of candy from the wheelchair kid in the hospital and give them to the two kids in the middle of the courtyard to achieve this.
In one of the very last buildings of the game is a room that has several encyclopedias. Giving the right one to the people in the courtyard arguing whether they're looking at mist or fog will earn this achievement.
There are 10 items in the game that can be smashed with a hammer; destroy them all to achieve this one. Nine of them are light fixtures in various buildings in the courtyard and the 10th is a vase located in a painting in a building when you enter the area past the guards.