Here is the full list of all 16 The Secret Monster Society - there are Chapter 1: Monsters Fires and Forbidden Forests achievements.
Complete Chapter 1
Fix the Time Machine
Escape the Forbidden Forest
Frighten an Animal
Start a Fire
Return a Ring
Acquire Loo Roll
Complete the Intro
Acquire an Adventure Ticket
Acquire the Breathe Easy 3000
Mix up some bug juice
Complete Chapter Two
Help Webby
Bring Albert a new broom
Find and Return Chef Lan-Lan's Book
Help the Stable Master find his wife