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