Here is the full list of all 27 The Gallery - there are Episode 2: Heart of the Emberstone achievements.
Pop a Wizgog without using the Arbalest.
Play the Cosmic Key.
Reunite the spectators of the Cull.
Collect, view, and read all the lore in the game.
View all the Polaroids in the game.
Give Hermie a new home.
Activate the Easter Egg.
Have a nap in the Transport Room tent.
Read all the stories of the people of Ember.
Kill every Wizgog in the Culling Grounds.
Build a small tower in the Culling Grounds.
Dismember 44 limbs.
Send a corpse down the shaft in the Tower of Cogs.
Complete every cog puzzle and unlock Sebastian's safe.
Obtain the Grasp.
Collect all the tapes in the game.
Kill the Mother Wizgog.
Meet the Beast.
Complete the game within a 93 minute runtime.
Solve every Gauntlet puzzle.
Repair the Solar Engine.
Complete Episode 2.
Finish the game without harming any Wizgogs.
Blast 10 corpses with a single Arbalest shot.
Kill the captured Wizgog.
Clear the crypt without using the flashlight.
Build a large tower in the Culling Grounds.