Here is the full list of all 33 A Fungus In My Garden achievements.
Unlock all achievements
Finish the Game
Finish the Game in Hard mode
Eliminate all Ruby Mushrooms (there are hidden ruby mushrooms throughout the maps)
Eliminate 1000 enemies
Finish a Level with no Damage taken
Finish a Level without using the shield
Unlock all the ruby mushrooms in the first level
Unlock all the ruby mushrooms in the second level
Unlock all the ruby mushrooms in the third level
Unlock all the ruby mushrooms in the fourth level
Cast 50 Ultimates (use the special Power from the Sword and cast it 50 times)
Eliminate 300 Enemies Melee
Eliminate 300 Enemies Range
Eliminate 500 Enemies
Cast 25 Ultimates
Eliminate first Enemy
Eliminate the First Fungus Leader
Eliminate the Second Fungus Leader
Eliminate the Third Fungus Leader
Eliminate the Fourth Fungus Leader
Killed by a Giant
Killed by an insect
Browse all the Gallery
Watch all the credits
Eliminate 100 Ranged enemies
Eliminate 100 Melee Enemies
Eliminate 250 enemies
Jump 100 times