Played this year and have been arrived at the 16th level "The Mansion - Under Seige" (the 15th in theory, but because I started from the Prologue level "Ruins - Mountain, Makalu")
There are a lot of references to the Final Fantasy World, especially the 12, and a lot of references to Silent Hill 3, because for example in the 4th level "The Sochen Cave Palace" there is a riddle concerning about series of numbers and must to put the solution to the keypad close to the door to open it and the solution is 4896, the same as like as the Brookhaven Hospital Keypad in Hard Riddle Mode.
Gameplay talking, this custom level is really unplayable, due to the fact that there are plenty of deadlines, no ways out, points of no return, where obviously the player, unconsciously and without his knowledge, does something that is not required by the game and he gets stuck, having to redo the whole part or the whole level.
Now I'm gonna to continue this misadventure and trying to finish it.
EDIT: I'm arrived at the 27th level (28 for me) called "One rainy night at the manor...". More craziness out of mind. OMG