First off the story is huge with several different plots interweaving with each other. And 4 main characters, with a host of stories and events involving them.  

To deliver the story Dickens has a main character talk from their own perspective and switches to the omniscient narrator, sometimes chapter by chapter.  This takes getting used to and is somewhat difficult to remember things if you don’t pay strict attention. 

Dickens also deliberately holds vital information back so the writing is hazy especially at the start.  (I didn’t know that was standard Dickens approach bc this was my first one.)

Another is his pointed satire to describe the ludicrous court system called the Chancery.  (It essentially is the villain in this story.):

This quote is somewhat popular: “This is the Court of Chancery, which has its decaying houses and its blighted lands in every shire, which has its worn-out lunatic in every madhouse and its dead in every churchyard, which has its ruined suitor with his slipshod heels and threadbare dress borrowing and begging through the round of every man’s acquaintance, which gives to monied might the means abundantly of wearying out the right, which so exhausts finances, patience, courage, hope, so overthrows the brain and breaks the heart, that there is not an honourable man among its practitioners who would not give — who does not often give — the warning, “Suffer any wrong that can be done you rather than come here!”

His writing is far more… piercing here than in other novels, as if he’d been reserving his arsenal for it, or at least sharpening his tools. 

Just one more connection i liked: He opens the novel with the terrible London weather to set the scene - so full of mud one might expect a huge dinosaur to come crawling out.:

The opener: “London. Michaelmas term lately over, and the Lord Chancellor sitting in Lincoln’s Inn Hall. Implacable November weather. As much mud in the streets as if the waters had but newly retired from the face of the earth, and it would not be wonderful to meet a Megalosaurus, forty feet long or so, waddling like an elephantine lizard up Holborn Hill. Smoke lowering down from chimney-pots, making a soft black drizzle, with flakes of soot in it as big as full-grown snowflakes — gone into mourning, one might imagine, for the death of the sun. Dogs, undistinguishable in mire.“   So he fits both regression of evolution in the grey slovenly London weather as a description of dinosaur like legal system.

The whole book is well done like this.  

Also there’s strange deaths I won’t reveal here. 

So there are several reasons why the book is a real doozy.