If you see a red barrel standing alone against a wall with no enemies nearby, it is almost certainly a marker for a secret. Blow it up to reveal a hidden passage. Exploration Tips
Follow any corridor that seems to lead nowhere; usually, the back wall is a destructible facade. Mission 3: The Lab
There is a hidden room behind the crates near the first keycard pickup. Mission 2: Deep Dark alien shooter 2 reloaded all secret place
Blast the wall behind the first computer terminal you encounter.
Shoot the flickering monitors. Sometimes they trigger a wall to slide open. If you see a red barrel standing alone
Before entering the main facility, check the far left corners of the fence.
Finding a rocket launcher or magma gun in a secret room in the mid-game can make boss fights significantly easier. Mission 3: The Lab There is a hidden
Walk along the perimeter of every large room.
In the large room with the central pillar, check the outer rim for a breakable panel.