Supernauts Mission Guide: Cairo - Mission 5, The Wall
Objectives: Rescue 2 Citizens, Rescue all citizens, Collect all Coins
Reward: 5 Coins, 308SP
Pick up the nearby Zapper and remove the pile of Bricks with it.
Go up the stairs to collect the Coin, then finish those same stairs with the bricks you picked up.
At the top you'll find a wall of Bricks. Remove them to find a Citizen. Then move to the right of this level to collect all the Coins.
Head back to where the shadow of stairs is, and make a set to rescue the trapped Citizen. Don't stop there though! Continue building upwards to the last Citizen, who is sat on the top of the wall (along with the remaining Coins).