Here is the full list of all 12 The Defenders: The Second Wave achievements.
Won the game on "Easy" difficulty
50 kills without taking damage
Have used over 3500 mana
Parried 50 enemy projectiles
Tanked 1000 hit points without dying
Killed at least 1000 enemies
Started a game
Unlocked trial mode, because the game is so good =)
Killed at least ten butterflies
Struck the moon
Won the game on Normal difficulty
Won the game on Hard difficulty