There are a few different types of secret rooms in various areas. Entrances can be triggered in a different ways (SPOILERS)...
- Breaking urns that have smoke rising from them can extend a vine bridge.
- In Dragon Stronghold, there was a lever on a platform sunken in the middle of the screen that can't be reached initially. There is a secret pressure plate in the floor within the outer octagon that will raise the platform.
- In the dungeon in the main quest line where you have to survive for the second task for the Djinni, there are two secret rooms. For the first, when the circle of light reaches the portal to go to the second part of the dungeon, do not go through the portal. Linger for a couple of minutes, and a lever will appear above the portal. When you pull the lever, the circle of light will begin moving again, with the same damage taken if you leave the circle, and take you to a room with two chests, then return you to the portal. The second is on the platform where the Manticore is fought. If you move along the northeastern edge, a small platform with a chest will rise, even during your fight with the Manticore.
- You can occasionally find tablets and picture frames that are clickable which lead you to a secret room.