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