Here is the full list of all 16 This Way Madness Lies achievements.
Defeat Lady Macbeth
Defeat 3 ZombieZombieDa
Meet a new ally
Defeat Yog-Titania
Defeat Krakenthulhu
Get a pet
Defeat Ursathulhu
Use a unite ability at 100% power
Fill 4 or more item slots with items
Complete a play
Answer a Shakespeare question correctly
Use the battle command
Defeat Rosebud
Use the chat command
Defeat Edward De Vere
Complete the game