Here is the full list of all 32 Deadlings: Rotten Edition achievements.
Complete 20 levels in Nightmare Mode.
Complete phase 4.
Complete all levels in Normal Mode with maximum rank.
Collect 200 stars.
Discover a crazy mutators.
Complete phase 3.
Discover a freezing freezers.
Collect 150 stars.
Complete 5 levels in Nightmare Mode.
Complete level 14 in less than 10 seconds.
Discover an awesome portals!
Collect 100 stars.
Finish 20 levels without killing a single zombie.
Complete phase 2.
Kill the zombie with the other zombie.
Discover a deadly lasers.
Unlock the Lazybrain.
Complete level 04 using one zombie.
Collect 50 stars.
Complete phase 1.
Collect 800 brains.
Kill over 100 zombies.
Collect 400 brains.
Unlock the Gasfat.
Collect 150 brains.
Unlock the Creep.
Complete all levels in Nightmare Mode with maximum rank.
Complete 45 levels in Nightmare Mode.
Complete 60 levels in Nightmare Mode.
Complete all bonus levels.
Complete all bonus levels with maximum rank.
Complete bonus level 10.