Where is the switch on Astro Knights Island?

Answer 1

There are TWO notable switches on Astro Knights island :

• In the castle library, if you have the Library Slip from the museum, you can enter the dungeon by clicking the McM shelf in the lower aisle. In the dungeon, throwing the wall switch opens the back gate to the cell, which you can later enter through a tunnel.
• Fighting the dragon on the Fire Planet, you must cross the chains and approach the dragon from the back. Throwing the lever on its back puts it "to sleep" for a few seconds. allowing you to shoot the Ice Arrow into its open mouth. (Unfortunately, you have to do this three times to kill it.)