Instructions
Open the item console and type in something to throw into the water to defeat the piranhas. You can type in "Poison," "Blob" or "Glue." Though these are not the only item you can choose, they will all work. Throw whatever you choose into the water and the piranhas will try to eat it and be defeated.
Jump in the water to break the first box and get the first piece of the puzzle.
Type in something to get you to the other side of the lake. You can type in "Bridge," "Jet Pack" or "Trampoline."
Type in "Gun." Use the gun to defeat all of the knights in your way. Once they are defeated, walk past them to the other two boxes and the end of the level.