So this book has altered a few things about the continuity about the books so first things first, i am going to give a definitive continuity.
Arrow (Sometime after Sins of the Father)
Legends of Tomorrow (Presumably not a thing yet)
Supergirl (Before Worlds Finest)
Now let us start the review with the positives.
The book shows a lot more stakes, and better action. They definetly had Barry's chances of dying from his plasma disease be much higher in this one. They also described much better fights than Flash: The haunting of Barry Allen. Another thing that was great was the fact that just like how the last one has Oliver in Barry's world. This one has Barry in Oliver's world. We also know more about our Arrow characters and unlike the Flash ones who wear their emotions on their sleeves, we get to know about characters who keep their thoughts hidden. Here are some examples.
Oliver: A SnowBarry shipper.
Diggle: A Christian.
Felicity: Feels like she is putting on the Green Arrow hood when she works her magic on a laptop.
Thea: Secretly is playing with Cisco.
Malcolm: Secretly a sore loser when bidding. He also makes amazing wine.
Another fun thing is the comic book references that the last book didn't have. We got to go to DC's fictional country of Markovia. We got to visit the castle of it's ruler Count Wallenstein, who served more as a Felicity antagonist than Oliver's. So that was pretty great.
Another new character introduced was Ghasi. Oliver's italian friend who serves Count Wallenstein and we get to learn more about him through the flashbacks. (yes, they are even in the books) This also allows us to see the annoyingness of Tommy again. (yay?)
One last thing that was great is that Cisco can vibe objects in this unlike in the last book where they didn't bring it up.
I'm going to start with the missing characters because i also ranted about it last time. Harry is not there again. This time they mention him, but they don't say why he isn't in it. When it comes to Arrow characters, Laurel is missing and if you look at where this book takes place, she isn't dead yet. Don't know why she can't be in it.
Also the book made Felicity a criminal. (before she even joined Helix or blew Havenrock) She basically faked the amount of money she had so she could get the device to cure Barry. So she screwed Palmer Tech at some point in time after they fired her. Good job Felicity!
A final thing is how idiotic Ghasi is. He hates Oliver for telling Robert Queen in the Flashbacks how Ghasi's father had given stuff to Markovia from Starling City. Even though Robert was going to go to jail if Oliver didn't tell him. Then in present day, Ghasi hates Oliver for stealing money from Markovia even though it was clearly Malcolm.
Finally the stupidest thing in the book is that Oliver deciding to wait outside in the cold until Barry was out of a blur. (It is when he is trapped constantly vibrating.) He didn't just have John do it even though Oliver is the one with the sleeveless costume. He should blame himself for passing out a couple of hours later.
Arrow: a generation of Vipers is a fitting conclusion to the two parter book series starring the Flash and Arrow. It has amazing action and characters, but some flaws like all books. Getting back to Legends reviews soon. (don't worry there isn't Legends books yet, though that would be cool)