Here is the full list of all 21 WhichWayOut? achievements.
You completed level 20
You completed level 19
You completed level 18
You completed level 17
You completed level 16
You completed level 15
You completed level 14
You completed level 13
You completed level 12
You completed level 11
You completed level 10
You completed level 9
You completed level 7
You completed level 6
You completed level 5
You completed level 4
You completed level 2
You completed level 3
You completed level 8
You completed level
You completed the game!