Under the Iron Cloud is the fifth level of Serious Sam 3: BFE.
Professor Stein's writings say that the secret to activating the Time-Lock is around the Pyramid of Khufu. After two helicopters have been shot down, Sam rejects air transport and elects to travel on foot. Unfortunately he's drawn the ire of Mental, who sends a new foe for Stone to conquer.
- At the pedestrian bridge — On the right side of the bridge is a building with a pickup on a third floor balcony. To get there jump onto the ledge of the ruined building just beyond the bridge, hop over to the target building, crawl under, then jump at the pickup to collect a clip of sniper rifle bullets.
- Near the pedestrian bridge — Just after the bridge, take a right into an alleyway. Hop on a box and over the wall to collect 3 C-4 explosives.
- Before the overpass — In a corner after the mosque is a garbage bag. Destroy it to reveal secret Electricity.
- After the overpass — Once off the overpass, head back along it. There's a garage with a car in it; look behind it for some minigun bullets.
- After the overpass, on top of a building — At the garage with a car in it, climb the boxes and then onto the building. Walk back in the direction of the overpass and around the corner. Hop on the air conditioner on your side, then take a sprinting leap to the air conditioner on the white building and climb onto the roof to find a cannon.
- After the overpass — Further back along the overpass there's a stack of barrels in front of a barb-wire topped wall. Jump over and pickup the weapon, spawning a Kleer Skeleton. The boxes are indestructible so you can always get out. This also allows you to return to before the overpass. (Alternate path: When still on the overpass, keep left, and sprint jump just past the grated fence up here, into the area of the lasergun below.)
- Perpendicular to the overpass — Along the road you get off onto after stepping off the overpass you can see a shipping container, and then left of that a portable with ammo on top. Climb the wall with graffiti on it, using the crates. Jump along the walls back to the shipping container and then over to the portable, and pickup the cannonballs.
- At the shipping container — Once on top of the portable (from secret 7), jump back onto the wall further away from the road after the vents. Drop down behind the wall to find a "useless secret area"*.
- After the underpass — There's a big fight along this road which has a mosque at the end of it on the left. On the right is a ruined building. Jump up into the window using the ruined wall to climb up, and then drop down and pickup the pill bottle. This spawns the message "Secret nuthouse found!" and at least 3 Major Bio-mechanoids. (Alternate path: Go all around the mosque to find two concrete barriers, these can be blown up with several rockets).
- After the underpass — At the end of the road after the underpass on the left at the corner of the mosque and the blockade is a secret armor hidden in some bushes.
- Before the drop down — Back along that road is a ruined car before a wall. Jump on the car and over the wall, and pickup the secret cannonballs.
- On a building before the drop down — If you look up on the third floor of a building before secret 11 you can see a pill bottle. Get back up on the wall, walk around the building, jump up onto your ledge, then jump across to grab the bottle.
- The ruins, far-right section — Along the right-hand wall near the far wall is some debris sticking out (not those ammo "refill" zones). Behind one of the chunks is a health pickup.
- On Tourist difficulty, there's a few rocket jump skips. First is firing a rocket at a tree near the start. Similar jumps are scattered through the level.