Here is the full list of all 47 DROD: The Second Sky achievements.
Touch the secret checkpoint in FW
Complete the challenge in SWaRBS
Complete the challenge in EoA:2E
Complete the challenge in EoA:3S
Complete the challenge in SM:4E
Complete the challenge in SM:1E
Complete the challenge in IU:1N
Complete Chapter 2
Complete Chapter 1
Receive an answer from the Truth Vessels
Complete Chapter 7
Complete Chapter 3
Complete Chapter 6
Complete Chapter 5
Complete the challenge in HitF
Complete the challenge in WBCEND:1N1E
Complete the challenge in WBCEND:1E
Complete the challenge in S.Ga.
Complete Chapter 8
Step kindly all the way through TLW
Complete the challenge in CW
Completed Bomberman challenge
Completed Roachu Rocket challenge
Completed The Second Sky and cleared all secret rooms
Looking for hard questions
Complete Chapter 9
Complete the quest for the plate
Complete Chapter 4
Complete the challenge in TRA
Be kind in HitF
Complete the challenge in GG
Complete the challenge in TO
Clear the secret area in SutO
Completed FB level
Completed R level
Completed all of Arky's challenge rooms
Completed D level
Saw the second sky
Complete the final chapter
The end of the journey
Complete the challenge in MOAR
Completed BM level
Complete the challenge in TH:1N5W
Complete the challenge in TH:2S1W
Be mean in HitF
Complete the challenge in EotS
Kill a man-eating dungeon roach