Piece of Cake

Facing the exit door, take the right door, go to the far right to a grid. Break the box to the left of it, a button reveals. Push it to open the grid. Behind is the secret.

Groovy

Right at the start, break the box to the left, push the revealed button, go in the vent, drop at the end to find the secret.

Under Every Stone

Go under the stairs for the secret.

What Else Ya Got?

In the first room with supplies, destroy the box, then move the table with the missiles on top away (by holding the right mouse button). Then push the button there to open the door which was behind the box. Secret is behind.



I knew it was here

In the room with the many boxes, jump down to the left and destroy the box, go through the vent and behind it is the secret.

Armed and dangerous

When you are in the first vent, go left. In the room, look up, there is a button. Take the three boxes in the room to make a little stairs underneath it. Then go on top. Push the button while jumping on the little stairs. It opens a door to an elevator next to it. Secret is downside. (There are enemies there.)

Uugh, Where Is It?

In the very first room, turn around. There is a button on the wall. Again, use boxes in this room to reach that. By pushing it, one of the two vents in the room will open. Behind that is the secret.



All I find is mine

Shortly after finding the axe, crouch underneath a little metal structure on the right side. Push a button and go through the opening. Destroy some boxes to the right and go through a vent to get to the secret.

Let's Rock!

In the long corridor at the beginning, jump on some boxes on the right side to push a button there. Now face where you came from and go in that direction. On the left a door has opened now. Secret is behind that.