Here is the full list of all 20 Arctic Cave achievements.
you collect key 18
you collect key 16
you collect key 7
you collect key 4
you collect key 20
you collect key 19
you collect key 17
you collect key 15
you collect key 14
you collect key 13
you collect key 12
you collect key 11
you collect key 10
you collect key 9
you collect key 8
you collect key 6
you collect key 5
you collect key 3
you collect key 2
you collect key 1