Italics are impressions from my first read, when I did not yet know what was going to happen.
1) Harry still can't find Ron and Hermione. I guess it's not such a "quickie" they're having. :p
2) Voldemort presents terms. He does not want to spill magical blood (he says). All he wants is Harry, and everyone else may go free in safety. I don't think I really believe him. His followers have been too free with the Cruciatus curse in the past. Besides this, if the school surrenders Harry, there's the snag that the world doesn't get any better.
3) Pansy's ready to hand Harry over. No doubt a number of the Slytherins agree. Funny how Draco was so reluctant to identify Harry a few chapters back. I'm willing to bet the Draco/Pansy 'ship ends with the war. I wish some of the Slytherins had stayed. I know they were likely to get the best deal under Voldemort's regime, but surely some of them have something resembling a conscience, and they can't all be pureblood, can they? Surely some of them have a muggle or muggleborn parent.
4) Colin Creevey. Again I ask, how is he there? He's Muggleborn, so he's not a student this year, and I doubt the Ministry allowed him to learn to Apparate this year either. His Muggle parents' house is probably in a Muggle town, and is not connected to the Floo network (which is monitored anyway). So how did he get to Hogwarts in time for the showdown?
5) Timeline. It just occurred to me that this is still the same day as they robbed Gringotts, isn't it? Wow. Long day. The trio must be worn out.
6) Battle strategies are in place. Dammit! I was so sure Chess Champ Ron was going to be in charge of strategy for the final battle. *sigh*
7) Harry forgot about the Horcrux. What a dummy! These people are risking their lives to buy him time to find and destroy the damn thing without even knowing what it is that he's doing, and he's just standing around with his mouth open. He's worried about Ron and Hermione. Awww ....
8) Harry dusts off his brain. He's trying to reason out what the Horcrux is and where it might be, but he's having trouble focusing without Ron and Hermione. He knows that Voldemort expected him to go to Ravenclaw Tower.
9) Zacharias Smith is an ass. She's pushing first years out of the way to be among the first to evacuate. I think he got himself sorted into the wrong house. Where's the Hufflepuff loyalty and fair play in this one?
10) Ghosts! I KNEW IT! Finally Harry does something really smart. How odd that he didn't even know who the Ravenclaw ghost was. He certainly knew who all the other ones were. But the Grey Lady has proved elusive and mysterious throughout this series. Have we ever heard her referred to within canon before now?
11) Helena Ravenclaw. Oh, I was so close! I thought she would either turn out to be Ravenclaw herself, or one of her first students. Somehow her daughter never occurred to me. Helena is beautiful and tall and long-haired and haughty and for some reason has her mother's surname. Who was her father? She smiles "coldly". She stole the diadem from her mother. Rowena sent a man who loved Helena to find her, and instead of bringing her back, he killed her. Well done, Mum! He then killed himself and became the Bloody Baron. Sadly, we do not get a name for him as well. I love getting Founders-era details.
12) The Grey Lady thinks Harry wants to *wear* the diadem. *imagines Harry in a pretty, pretty tiara* She told handsome young Tom Riddle where it was when he turned his charm on her, and he retrieved it from the hollow tree in Albania (which was apparently still there a thousand years later). She's telling Harry now, because she regrets telling Riddle. She never told Dumbledore because he probably asked about it without mentioning Voldemort, since he was trying to keep his Horcrux quest as secret as possible.
13) "Oh, don't mind me ... I'll just lie here and crumble ...." Awww...I adore the snarky gargoyles! I hope they get repaired with the rest of the school one day.
14) Out of nowhere, Harry remembers where he's seen an old tiara. Lucky he saw that at the end of last year, eh? He could have hidden his old potions book anywhere in that huge room, but he managed to see the Vanishing Cabinet and the diadem of Ravenclaw just by chance.
15) "Dumbledore and Flitwick, those model pupils..." You wanna bet? Just because they never got caught .... But we know that Dumbledore didn't know about the Room of Requirement, per se.
16) Sprout, Neville and the mandrakes. They're going to throw them over the walls. But...when the pots burst, aren't some of our friends going to hear the screams as well? Seems like a rather desperate plan.
17) Fred and Co., guarding the secret passageway. I hope Fred and George brought a whole bunch of merchandise with them.
18) Aberforth suggests that maybe keeping a few Slytherin hostages would have been a good idea. It's not terribly noble, but it would have been a pretty smart idea. McGonagall didn't think of that? I suppose she knows that Voldemort knows that none of them would hurt any of the kids, no matter what happened.
19) Ron and Hermione were not bonking after all. They've been to the Chamber of Secrets. WTF?! Ron FAKED Parseltongue?! That's the most f***ing ridiculous thing I think I've heard in this entire series. Parseltongue is not a language you can learn or speak just because you want to; it's a magical skill that you're born knowing. If I speak gibberish with a French accent, it's not the same as speaking French, but apparently Ron can just hiss at the chamber entrance and that's good enough. I'm telling you right now, that wouldn't have worked on the basilisk. Also? How did they get back out again? They had Fawkes to carry them out last time. Anyway, now they have some handy basilisk fangs with which to destroy Horcruxes.
20) The Hufflepuff cup is taken care of. Hermione got to do one this time. Wait a minute ... Dumbledore destroyed the ring, Ron the locket, Hermione the cup, and the others ... well, we'll get to that. But so far the only Horcrux Harry's destroyed was the diary, and he didn't even know what it was at the time.
21) Tonks. She's left the baby and come to join in the fight. No, sorry; she's come to look for Remus. Isn't this woman meant to be a trained Auror or something? Be USEFUL, woman! Then maybe I won't want to smack you so much. Even Ginny wants to go out and fight and not just be with Harry. Is that DOOM I smell? Time to make another war orphan, so we can neatly bookend the series with another mirror.
22) The Room of Requirement. The passage into the Hog's Head has been sealed by Gran Longbottom, who seems to know how the Room works pretty well herself. What's up with that? And now Harry needs to clear the room in order to transform it? No he doesn't! It should change into whatever he needs, even while he's in it. All he's got to do is get everyone there to ask for the Hiding Place.
23) Ron/Hermione snog! About bloody time, too! Apparently showing concern for House Elves turns her on. "OI! There's a war going on here!" Sounds like the right time to me ....
24) Aberforth: "He's dueling Dolohov [...] haven't seen him since!"
Ginny: "I'm sure he's OK --" Shit .... After reading the webchat with Jo .... I guess this was when it happened. *hugs Remus* He's with Sirius now.
25) Malfoy, Crabbe and Goyle. I don't understand exactly how they got into the Room. We saw how much trouble Harry had getting into the Room while Draco was in it last year. How did Draco know Harry was in this version of the Room?
26) Narcissa gave Draco her wand. She protects him even when it means leaving herself defenceless.
27) Crabbe: "I don't take your orders no more Draco." Aww... Crabbe's breaking up with him. Stupid of him. The trio will be united against them; now is not they time to go splitting themselves up, is it? Crabbe turns out to be a right nasty git, doesn't he? He went and cast Fiendfyre which, coincidentally, is one way of destroying a Horcrux. Lucky, that!
28) Broomsticks! Oh, here we go.... I *knew* Harry's awesome flying skills would come into play somewhere along the line. Look! He's *seeking* a *small, shiny object* from a *broomstick*. Does that remind anyone of anything?
29) Draco is behaving like Snape. Despite Crabbe's rejections, he does his best to help him and Goyle, even after he himself is disarmed, and does not try to attack the trio himself. And him with his arms around an unconscious Goyle .... :p He didn't try to make a run for it himself, but stood by his friends, and was upset that Crabbe was killed. How about that? I don't think it means he's a good person or that he'll suddenly stop being a bigoted bastard, but that doesn't mean he's without some virtues.
30) "IF WE DIE FOR THEM, I'LL KILL YOU, HARRY!" Oh, Ron! *giggle* Harry is desperately searching for the Slytherins, and thinking that death by fire is too terrible a fate to contemplate for them. He spies Draco and Goyle and swoops in to save them. So what I don't get is this: Harry + Draco + Goyle is too heavy for one broom, but Ron + Hermione + Goyle isn't? Is there really that much difference in weight? Or did Jo want to give Harry and Draco a "moment"? :p
31) The diadem. Harry grabs it in midair, just like a Snitch. How fortunate that it happened to turn up again and that they saw that it was destroyed!
32) "Malfoy was screaming and holding Harry so tightly it hurt." I'm sure I've seen similar in about a million fanfics, but the circumstances were always a bit different from this. :p H/D 'shippers really are dancing in their happy socks here, aren't they? I haven't dared venture into the realm of H/D postwar fic, but I'm betting there was a serious boom brought on by this scene.
33) The Room's fate? Is it gone now, destroyed by Fiendfyre? Probably. But maybe not. Maybe it's just waiting for the next person who needs it. What would happen if you told it now that you needed the Hiding Place? Would it appear all burnt out, or would it reform as it was before the fire, but with objects created by the Room replacing the ones hidden by students?
34) Percy makes up for lost time. I love his comments to the Imperiused Minister. He can be as snarky as any Weasley. Fred is delighted. But then.
35) Rocks fall. Fred dies. I so called it! And I was too pleased about the fact that I was right to feel very sad about it at this moment. There's just too much else going on. But this time, I felt a definite pang, especially because Fred died laughing, which is very much as it should be.