I'm still back on level 3. I have the Whistle, and a spare key, but I can't seem to get any further without a magical boomerang. I can see a big chest in the bottom row of rooms, but I can't seem to figure out how to reach the room directly above it (Which is one screen south of the kitchen).

All these invisible passages are driving me mad. It'll be nice once I finally have the Lens of Truth....

-SirNiko