Here is the full list of all 15 Noctropolis achievements.
Defeat the arch-villain
Discover the Whisperman
Find the Neon Noose
Find Dynatek and Incarnate's ruins
Escape the Drealmer's dream world
Escape Master Macabre's maze
Kill Master Macabre
Survive the assault of Tophat
Find the Bornick Mansion
Shut down Greenthumb's greenhouse
Become the new Darksheer
Team up with Stiletto
Defeat the Succubus
Befriend Father Desmond
Reach Noctropolis