• Dawn of Sorrow
  
• Floating Knight
  
• Evil-Eyed Giant
  
• Candidate Count
  
• Obsidian Wings
  
• Flame-Wielding Candidate Count
  
• Lord of Puppetry
  
• Caught in the Cradle of Decay
  
• Giant Fish of the Underground
  
• Manipulator of Time
  
• Horde of Terror
  
• Clown in the Mirror
  
• All-Consuming Flames
  
• Confidant of the Underworld
  
• Purveyor of the Plague
  
• Beyond All Calamity
  
• A Promise Fulfilled

• Portrait of Ruin
  
• Night Museum
  
• Rotten
  
• Sticky
  
• Temptation
  
• The Cog and the Crowd
  
• Warring Sister
  
• Water Evasion!
  
• Soul-Reaping Scythe
  
• Sisters of the Sanctuary
  
• Missiles and Machine Guns
  
• I am Pharaoh
  
• Do Not Make Eye Contact!
  
• Fangs that Pierce the Darkness
  
• Divine Bloodline
  
• Master of the Castle and Painter of Souls
  
• Perhaps the Strongest Team
  
• As Long as We Are Here
  
• Vampire Hunters

• Order of Ecclesia
  
• Rotating Shrimp
  
• Enormous Human Bones
  
• The Lighthouse and the Crab
  
• Cranium-Nesting Monster
  
• Monster Lurking in the Sea
  
• Blasphemous Giant
  
• Monster that Swims Underground
  
• Beloved Siblings
  
• Farewell to the Master
  
• Monster Living in the Wall
  
• Demon Controlling the Shadows
  
• Gargantuan Champion
  
• Administrator of Dying
  
• Apocalypse Glyph
  
• Wielder of Magical Gun Agartha

A simple enough guide for simple enough achievements, if not in execution then definitely in implementation - just play the dang games, and you shall achieve to your heart's content. About the only point of disappointment from me is that Portrait of Ruin's only got one extra achievement for game-mode clearance, given it has four game modes compared to the others' two. Like, what if I wanna show people I beat the game as the two secret modes? Take pictures and post incessantly about 'em? Maybe. But then, what can ya do? ¯\_(ツ)_/¯

Personally, I count myself lucky they didn't add "Get All The Things" achievements. That would've probably dealt some damage to my poor psyche 😓