One of the many trophies and achievements that you can unlock within Serious Sam: Siberian Mayhem is Sam the Explorer and No Stone Unturned.
This requires you to find all 85 hidden secrets, this includes ammo depots, T.A.C.T. Traps, Hoverboard Scooter, Rage Serum.
Below is a list of chapters where you can find these secrets and how to find them..
LIST OF MISSIONS:
- Chapter 1 – A Smell Of Petroleum Prevails
- Chapter 2 – The Song Of The Stormbringer
- Chapter 3 – Siberiade
- Chapter 4 – Roadside Picnic
- Chapter 5 – Crime and Punishment