This level has only 1 secret that can be collected after completing the main campaign. In your first playthrough you wont be able to collect this secret.
Secret 1 (Can be collected only after completion of Main Campaign)
This secret is near the location where you exit the underground area. Before the exit you’ll come across a small library. In the library interact with a book to open a secret door. Go inside and collect a Secret Rune. Collecting 9 Runes will unlock a Secret Cow Mission.
