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