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