[9-12] E2M2: The Ogre Citadel

Near the beginning, after descending the first staircase, jump into the river. Head left into a small cave and walk to the back wall. An elevator will take you up to a +100 health box.

From where you found the +100 health box in secret #1, continue into the water. Exit the small room you are in and go left. Keep going left along the path, under the bridge, and into the small room on the far wall. Go up the stairs to find a grenade launcher.

At the end of secret #2, you will exit the secret room into a hallway. Go slightly to your right, and on the right wall, there will be a window. You will see an Ogre across from you. Jump out this window, staying close to the wall to land on the bridge. Follow the bridge, get the armor, and keep going to find a +100 health box.