The Peninsula


Hint: Use the reflectors to destroy 1 wooden box.

Full Solution:


First use Stinky to push 1 wooden box (yellow X) and 2 steel boxes (green X) into the water to gain access to the conveyor button (upper right). You'll need to wait until the rolling boulder is headed for the red button (red circle) and then stand on the conveyor button, so that the boulder stops on the red button.
Now use Stinky to pick up the 4 bonus coins and then enter the green teleporter - enter from the left side (purple arrow). This will push the reflector into the water (near the island below) - you'll need to time it so that you don't get hit by a fireball! Now move Stinky back through the teleporter.
Switch to Loof and get the key that is blocking the fireballs from hitting the wooden boxes. You'll need to destroy 1 box and push the remaining 3 through the red teleporter, avoiding fireballs as you go. Push 1 box into the teleporter from the left and the remaining 2 from the bottom. Now send Loof through the red teleporter (from the right), push the box in the water at the top, and get the remaining keys. Switch to Stinky and have him move the steel box in line with the boulder by the blue button. Place the box above the little island with the green button. Now use Loof to push the boulder towards the steel box, stopping Loof on the blue button. Have Stinky push the boulder and steel box into the water, creating a bridge to the little island. Now open the green gate with Stinky and send him through the blue teleporter, then the red teleporter, and then exit. And last but not least, send Loof through the exit. All done!