The flame monster must be locked in a
path around one fruit.
At the bottom of the room.

Release the rolling skull monster.
The flame monster will kill it.

Use the hammer to break the remaining
green fruit.

Here go right only breaking yellow
fruit blocks from the upper row.

Remove all remaing yellow blocks
while going back to the left.

Lock the flame monster in a path around
one green block.
Make it fly to the right by
removing the green block.
The flame can destroy the ice block
which contains the mystery.