Full list of all 52 Sker Ritual achievements.
The base game contains 46 achievements, and there are 2 DLC packs containing 6 achievements.
Find the hidden music on House of the Dammed
Complete House of the Dammed on Nightmare
Complete the hidden objective on the House of the Dammed
Complete all of the Hidden Music Objectives on every level
Unlock any Weapon Skin Level 4
Complete the Tides of Terror Hidden Story on Nightmare