All the secrets are the same as regular Karnak, with the exception of a new one:
New Secret: When you encounter the sleeping Adult Arachnoid, slumbering over an Ankh, you can either shoot it with the rockets from the Secret Generous Yard (before picking up the Rocket Launcher in the room) for a regular Secret, or walk into the room until the door closes and then attack it (before picking up the Rocket Launcher in the room) for a "Brave Secret".
- When the level starts, instantly move backwards to find a "generous yard". There's some ammo and various items and enemies there.
- In the first room, there are 2 switches behind 2 columns, one on the left and one on the right sides of the room. Press both switches to lower a platform next to the door where you entered from, which will then lift up again, transporting you to a secret area.
- In the Ankh Pool, dive in, there's a differently colored part on the floor of the pool. Touch it to reveal a secret room.
- On the right side of the Ankh Pool, on the wall, is a differently colored part. Touch it to reveal a Croteam Papyrus.
- After swimming through the pool into the temple, turn around. Go to the left and right corners are some switches, press both of them to open a secret door near the Obelisk, in the middle of the Ankh pool. The door leads to a room with a blob-like thing and an item.
- Before the Marsh Hopper fight, in the room with the two pools, dive in the pool on the left, and touch the differently colored wall to reveal a path to a spherical room with abnormal gravity. (in Serious Sam HD, this room has normal gravity.)
- In the last area, there is a differently colored small spot on the wall on the left. Walk through it to find a secret ammo pack.
- Eventually, in the last area, it will say that the "Secret Health has been Enabled" at some point. It is opposite of #7, pick it up to register the secret.
- In Test 1, the level is part of the Karnak Temple Complex chapter. This specific level was called "The First Pylon".