|-- Jan Mayen Island|
-A cut scene will show you the spiral path downward. Use the outside edge to avoid the various sized holes. Ignore enemies.
-I actually fell down one of the holes (on easy), survived and got there faster than intended.
-If you are collecting everything for your first play through, grab the treasure to the right, then dive over the edge to die on purpose to reset the time. You'll start back up top to retry your challenge.
-Again, not too hard. Just don't let obstacles slow you down.