Here is the full list of all 41 Lamplight City achievements.
Played through the entire game without opening the casebook
Checked yourself into Riverview Asylum
Declared a case unsolvable
Sang a popular drinking song
Correctly solved every case
Every friendship has one
Confronted the Justice Killer in his own home
Found every single clue and document in the game
Eavesdropped on every conversation
Completed the game
Ended up in jail
Accused Jimbo of murdering Ronan L'Espaye
Told Adelaide the truth
Accused Tom Puffin of murdering Ronan L'Espaye
Discovered the truth about the cooping scheme
Read every book in the game
You voted!
Concluded that Desiree Lathan's death was due to spontaneous human combustion
Accused Margaret Andrews of murdering Desiree Lathan
Showed Desiree's ashes to someone who wasn't Dr. Edwards
Told Patrick a story
Accused Roger DeVay of murdering Desiree Lathan
Tricked Jonas Usher
Gave Charlotte Robineaux a music lesson
Spoke with Roland Deveraux
Accuse Arthur Devins of kidnapping the Harris baby
Accused Malcolm Harris of kidnapping his own son
Successfully located Linda Walker
Accuse Linda Walker of kidnapping the Harris baby
Fixed the boiler without any help
Told Angela Maxwell about your problems
Learned about Mrs. Davis's hobby
Accused Guy Dumas of Madame DuPrée's attempted murder
Accused Albert Martin of Madame DuPrée's attempted murder
Accused Juliette Montgomery of Madame DuPrée's attempted murder
Kept your promise to Mrs. Hanbrook
Revealed Madame DuPrée's true nature
Got kicked out of Sabine Martin's apartment
Read Madame DuPrée's poems
Played a familiar melody
You're so annoying