Good habit in this game to shoot every lantern which as you think will clarify exact area you need to sea. Lanterns light up much more than just a lit and holded arrow in your hands ) Hanging skulls could be also more useful, if first upgrade for them would be "+1 coin every next shot of arrow", and 2nd upgrade "coins are multiplied x2 each next arrow shot" ) I think these are more interesting upgrades than same few "chances for double arrow"