use the axe:
change it sprite then create an event triggered by the axe/whistle's death
in the event, use the special event WI.ADD (warp whistle)
to exit the level use the laers: create an hidden layer that will apear at the same time than the previous event: in that layer, put an exit item in the same location than the "axe"
for the world use, i can't help you, i've never used it.