The novelization is apparently filling in some holes left from the film along with some new things not seen in the movie- (thanks to Darth_Monopoly for the following post)-
The opening is Leia wondering where Luke is and trying to call out to him that she needs him.
-Snoke mentions having seen the Empire rise and fall. If that was in the movie then I missed it.
-Leia is informed of the FO’s attack on Jakku and Poe’s assumed death. She is upset and does not want the FO to find Luke before they do. She knows that BB-8 is still missing so she asks 3PO to activate his tracker to find him. She then sends her envoy to the Senate in the Hosnian system to ask for help, explaining that she cannot go herself because while she still has friends there she would likely have an unfortunate “accident” because many there do not like her.
-There is a scene with 3PO talking to the low power R2 where he is basically talking to himself but asking what R2 would do, because he forgot to activate BB-8’s tracker before he left on the mission. He decides to send a message to all active Resistance droids to be on the lookout for BB-8.
-We get a scene of Poe waking up after the crash. He has a concussion and it turns out that he got out of the TIE after crash landing it and wandered away before collapsing and it’s just bad luck that Finn didn’t find him. There’s a whole sequence where he meets a scavenger who decides to help him and then they are attacked by other scavengers and Poe pilots a speeder showing off his skills again to get away.
-Unkar Plutt finds Rey at Maz’s Castle. He found them because he had a homing device on the Falcon. Rey tries to use her blaster on him but the safety is on. Chewie intervenes and tears Plutt’s arm off. It’s at this point that a droid sees BB-8 and sends a message to the Resistance.
-Then there’s a quick scene with 3PO receiving the message and informing Leia of BB-8’s whereabouts. These 3PO scenes are both good but I think I prefer his first appearance in the movie.
-A scene of Leia being informed of the the destruction of the Hosnian system and feeling the deaths of all the people in the Force. And she thinks about how no one should be subjected to the death of an entire world but she had been subjected to two and she would not allow it to happen again.
-Also, it’s not as easily seen in the sky above the Castle. That was one of my problems with the movie was that it made it appear that they were in the same system.
-Confirmed Han and Leia are husband and wife.
-General Hux launches something called seekers to take out the attacking X-Wings on Starkiller Base. He’s warned that they will take down TIEs too but he claims that collateral damage will be necessary to win.
-There’s a chase sequence involving the stolen snow speeder that Rey and Finn use to get to the oscillator.
-Kylo Ren removing his mask for Han is the first time Han has seen his son as a grown man. Also, Han debated leaving without confronting him but didn’t because he wanted to fulfill Leia’s request.
-Poe does not fly into the oscillator and there is no “trench run”. His pilots simply bomb the hole that the detonators exposed.
-Hux rescues Kylo Ren and could have taken Finn and Rey but there was no time and his instructions from Snoke took precedence. He assumed they would die there anyways.
-The doctor tells Rey that Finn will be fine although he is in a medically induced coma and nothing is certain until he fully recovers.
-R2 has the rest of the map because he catalogued the Imperial archives. He overheard a discussion of how Kylo Ren had said that they held the rest of the map because it was in the archives. He then powers up and displays the map.
-Rey has a conversation with Leia before she leaves where Leia promises her that she will not share the fate of her son.
-Rey extends the lightsaber towards Luke as an offer and a plea because he’s the galaxy’s only hope. She wonders what will happen next.