Grimrock

It's all the alcoves where the skeletons are trapped that matters. 9 in total. Have you gotten into that area or not?

Level 1 = 5 secrets
Level 2 = 7 secrets
Level 3 = 5 secrets
Level 4 = 5 secrets
Level 5 = 4 secrets
Level 6 = 5 secrets
Level 7 = 1 secret
Level 8 = 8 secrets
Level 9 = 2 secrets

Level 1 = 1 treasure
Level 2 = 1 treasure
Level 3 = 1 treasure
Level 4 = 1 treasure
Level 5 = 1 treasure
Level 6 = 1 treasure
Level 7 = 0
Level 8 = 2 treasures
Level 9 = 0

1. Feed the prisoners when you are warned to not do so. If you have removed the food in the alcove you'll end up in the same room as the ogre. But, the ogre is behind bars. Pulling levers you will open gratings and find a way out. Next to the teleporter out there is an alcove. Put something in it and a secret wall opens to reveal a secret.

2. After the altar for the goddess of the thief's moon you need to pass a pit that opens and closes. One of those pits are closed by a secret button found when you teleport around killing crowerns.

3. After the teleporter maze you find the Altar for the goddess of thieves. In the room that opens there are several alcoves with things in them. Remove the things and put something back and a secret door will open.

4. Fireball room. Find the small secret button, and let the fireball spawned hit the receptor. If a monster get in the way you need to press the button again.

5 and 6. The pit room. There is a note somewhere that tell you to drop things in pits. Easiest is to drop something in all pits. Two pits will close so that you can pass. One in the same room as all the pits, to the east. Another at the very start of the room where you entered, to the west.

7. The iron door. Putting something in the pit near the altar for the god of the frozen underworld will open a secret door further away. Later when you get back to level 2 (from level 3) You'll find the lever for the door at the end of a corridor, the same corridor where you find the secret button that opens up for the catacombs.

1. "Planning and timing is key." Put a gem in the mouth of all four daemon heads and a secret door will open at the end next to the stairs that lead up again.

2. When you drop down from the altar of the god of the frozen underworld you end up in a long corridor with lots of secret buttons. Find all buttons and a secret door opens close to the end.

3 - 4. Opening all doors with the gem heads you'll end up at a row of altars. Filling all altars opens a door. That's one secret. In the room there are several alcoves. Fill them and another secret will be revealed.

5. The iron door, opened from the area of 3-4.

That's the secret where you need to drop something in all pits. There are pits behind gratings that need to be filled too.