Here is the full list of all 20 Monsters Love Candy (Windows) achievements worth 200 gamerscore.
You fed the first Monster you found in the Forest.
Win 10 multiplayer games
Use every Boost in the game
Play 100 games
Customize your Monsters or Candy from the Store
Reach the Desert World
Evolve a Mythical Monster
Acquire Monster Research L1 in the Store for all 10 Boosts
Win 50 multiplayer challenges against Random opponents
Have 10 Friends playing the game
Evolve 200 Monsters
Have all 15 Crowns in any World
Use 10 different Legendary Boost Monsters
Return to the game 10 days in a row
Evolve all Monsters in a World
Reach the Tundra World
Get promoted to Research Level 30
Visit the last Location in the Coastline World
Earn 3 Stars in all Locations in a World
Earn 225 exploration Stars