Level 13. Unfriendly Skies (2)

In the baggage claim, jump onto the track. When you see a red button on the right, jump off the track and push the button. Quickly jump into the open panel before it closes.

Inside the "Impulse Gifts" store, interact with the cash register. A panel in front of you will open, revealing a fortune cookie.

In a room containing 3 phones, 3 Pachinko machines, and two dispenser machines (one black, one blue), jump onto the Pachinko machines, then onto the black dispenser machine. Access the open panel. If this panel is not visible, you must first obtain the red pass key from inside the airplane cabin, use it on the elevator door, and ride the elevator.

In the control room, jump onto the coke machine, then jump left onto the dispenser machine. Face right and shoot the button on the dispenser machine to reveal items.

In the area with numerous Pachinko machines and an airplane cabin, face west and shoot the button on the eastern side of the three isolated Pachinko machines. Jump onto the machines and enter the open panel to find a Missile Launcher.

Locate the room containing the plane's engine. Jump and interact with the engine to find a panel that opens, revealing a rail gun.

This secret leads to the second hidden level, Level 22: Auto Maul. Follow these steps to reach the secret level end switch:

• Find the elevator with signs "Gate 21A" and "Gate 21B" above it. Push the button to make the elevator arrive with its doors open.

If you can push the button, walk out of the elevator, then back in, you can position yourself on top of the elevator. There is a switch located there; hit it so the elevator will transport you to the top, where the secret level end switch is located.