Here is the full list of all 106 The End Is Nigh achievements.
Collect 50 Tumors
Collect 100 Tumors
Collect 170 Tumors
Collect 300 Tumors
Collect 450 Tumors
Complete The End
Complete The Arid Flats
Complete Overflow
Complete The Wall of Sorrow
Complete Retrograde
Complete The Hollows
Complete SS Exodus
Complete The Machine
Complete Golgotha
Collect all Collectibles
Complete all Cartridges
100% All Cartridges
Do it all!
Complete the main game with under 200 deaths
Complete the game in an hour and a half or under
Complete Morta Man
Complete Morta Man without using a continue
Complete Morta Man with 50+ rings
Complete Morta Man with 100 rings
Complete Blaster Massacre
Complete Blaster Massacre without using a continue
Complete Blaster Massacre with 50+ rings
Complete Blaster Massacre with 100 rings
Complete River City Rancid
Complete River City Rancid without using a continue
Complete River City Rancid with 50+ rings
Complete River City Rancid with 100 rings
Complete Ash Climber
Complete Ash Climber without using a continue
Complete Ash Climber with 50+ rings
Complete Ash Climber with 100 rings
Complete Rubble Bobble
Complete Rubble Bobble without using a continue
Complete Rubble Bobble with 50+ rings
Complete Rubble Bobble with 100 rings
Complete Catastrovania
Complete Catastrovania without using a continue
Complete Catastrovania with 50+ rings
Complete Catastrovania with 100 rings
Complete Fallen Fantasy
Complete Fallen Fantasy without using a continue
Complete Fallen Fantasy with 50+ rings
Complete Fallen Fantasy with 100 rings
Complete Morbid Gear
Complete Morbid Gear without using a continue
Complete Morbid Gear with 50+ rings
Complete Morbid Gear with 100 rings
Complete Dig Dead
Complete Dig Dead without using a continue
Complete Dig Dead with 50+ rings
Complete Dig Dead with 100 rings
Complete Denial
Complete Anger
Complete Bargaining
Complete Depression
Complete Ghosts n Grieving
Complete Spike Tales
Complete Scab or Die
Complete Tombs and Torture
Complete Pus Man
Complete Dead Racer
Beat the full game and all carts
Collect Iron Cart I from the unknown
Collect Iron Cart II from the unknown
Collect Iron Cart III from the unknown
Collect Iron Cart IV from the unknown