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