Warlock's Tower

This is the final area of the game, and this achievement should unlock upon completing the last stage (assuming you completing every other stage in the Chambers) but this achievement seems to be glitched across the board for everyone, in that it doesn't unlock after completing all Chambers stage. To fix this, after you've completed the game, close the game app. Relaunch the game, and Continue so you're back at the level select screen. The achievement will then unlock.

Refer to the "Beat the Game" achievement solution for more information.