What are the differences between the show and the novel?

There are a lot of minor ones, the screenplay basically takes the major plot points of the novel and rewrites the intervening bits. A couple points that stand out:

Teng Zi Jing isn't really a character in the book. He does exist in the book but he's just a guard to the Fan family and doesn't really have a real relationship to Fan Xian. He also doesn't die (at least not in the timespan of season 1). His death was a pivotal plot point to the screenplay, adding motivation to FX's actions so in some way the lack of his death fundamentally changes FX's characterization.

Fan Xian is darker as a character in the book. He's more of a pragmatist who will ruthlessly destroy anybody against him and less of an idealist who wants to improve the world. For instance, he himself tortures Si Li Li in the book which was removed and reversed in the screenplay. He also doesn't have the same reaction to his mother's words on the monument where it seems like he embraces her vision of an improved world. 

Yan Bing Yun never stabs FX in the book (at least not in season 1). The whole thing just doesn't happen, they make it back to the capital without incident. I don't know what ramifications the stabbing will have. 

The book goes into way more detail about FX's qi techniques and whatnot. This could be a plus or a minus, depending on how much you like learning about qi techniques.

When I say not in season 1, I just mean that I haven't finished the book but I've gotten most of the way there and waaaay past where season 1 of the screenplay ends. 

The overall plot is pretty similar and I'd say all of the main characters are very similarly written in both versions other then TZJ. 

Thanks for sharing what you have read so far. I understand it's long book and I'm not sure I want to read it.  

It's interesting you say FX is darker in the book, because I have theorized that in the show he might be the bad guy or at least having growing pains as he grows into a leader.

Well in the season 2 I do expect FX in the darker character as he go through with betrayal, death, sad and so on. I am really expecting the drama the most.

To say the truth this is the 1st CDrama  which impressed me a lot and am really looking forward to S2.  I liked the actor who acted as FX and iam going to watch his dramas later.

 Singularity:

I know, I'm pretty pumped by S2, I hope they don't screw it up. 

I stopped listening to the audiobook with about a third left but the plot is definitely better in the second part of the book compared to the first part so I'd expect season 2 to be a good bit better then season 1 (assuming they don't screw it up).

well hope the drama to be produced in 2021

I'm just hoping they keep the Harem. Because for some reason I'm not a big fan of Linger ! 

 Singularity:

I don’t think FX and Duo Duo get together in the book? Don’t know for sure since I only got about two thirds through the book. He does have a harem but mostly with minor characters who have already been cut so I can’t imagine they’d add them back in retroactively.

Duo Duo is my fav character in the both the book and the drama though, their relationship is so much more interesting then the FX-Wan’er relationship.

Anyway, Linger bores me.  And I have gotten to a point in my drama journey where I actually found that I like Harem stories in historical dramas it's more fun sometimes watching the wives duck it out lmao

I can remember if this was answered but is the novel translated in english ?