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