You have a lot of legitimate concerns reapersaurus, but I'll try to explain those that are better explained in the book. Some are just bad Hollywood moviemaking, and some are inherent in the differences between the film medium and the written medium.
reapersaurus said:
Each time they have a dark element, it jars me out of this happy, safe, kid-like heroic story-world that they presented in the first film.
Get used to it. It only gets darker from here. There is still a kid-like story-world, but it has some seriously dark currents running through it.
For example, why would they repeatedly show spiders leaving the scene of the crime, and NOT have Harry follow them? Or even point them out to his 'trusted' superiors?
If they AREN'T trusted (i.e. Dumbledore), than they have just broken one of the conventions they established in the first film.
Would you climb out the window of a castle to follow a bunch of spiders? They were likely not on the first floor you know.
Besides, you have to bear in mind that due to the nature of movies, anything that is mentioned is automatically emphasized, because a movie is short and time is a premium. However, in a book a lot of things can be mentioned without emphasizing them, because there's over 200 pages full of text and description.
Harry and his friends also have an unfortunate tendency to try to fix things themselves. They trust the elders (well, Dumbledore anyway) but aren't completely forthcoming about everything they know and observe, for a number of reasons.
Further, why WERE the spiders there at the scene?
They weren't involved in the crimes (as established in the "Spider-Scene"), so why did they show Harry repeatedly seeing them leaving a proverbial trail of crumbs that he kept ignoring?
Coincidence? The spiders fled because they were afraid of the basilisk. I don't recall if Harry and company saw the spiders leaving at the scenes of the petrifications in the book, or if they saw them at some other time.
Why is Hagrid friends to an army of Evil spiders? (eating schoolboys qualifies as a sign that they are Evil, in my book, how bout yours?)
Hagrid is a real softie when it comes to beasts. He doesn't see them as dangerous, because they're all softies inside. When he sent the boys to Aragog, he thought he was sending them to a friend who would help them.
I was confused at the end of the movie - Harry calls the older Slitherin "Malfoy" - I'm sure of that.
But when I heard it, I could have sworn I remembered them calling the younger blonde boy Slitherin "Malfoy"?
They're both Malfoys. The young one is Draco Malfoy, and the older one is his father.
1) Why would Harry even think about going back to those horrible people during the summer? They showed him being systematically abused, and then send him back home at the end of each movie??!
Because he doesn't have a choice. They're his guardians, as he doesn't have any parents or relatives. In the books you get a definite feeling that Dumbledore has other reasons for sending him back to the Dursleys every summer.
2) Why did Dobby go WAY out of his way to 'protect' Harry?
Because Dobby's an idiot.
Besides, you're assuming that Dobby knew exact the nature of Malfoy's plans, which may not be true.
4) It was jarring to have the Tree they smashed into be such a menace.
Why would they allow these things on the schoolgrounds if they would kill the kids that go there?
There's a reason for this, but I'm not going to tell you what it is, as it doesn't come out until later.
Rowling has an amazing ability to tie all her books together. There are little comments and descriptions that seem to be just interesting fluff or description, but which take on whole new meanings when the events of later book take place. I'm sure there are things that I breezed over in the first four books that I'll suddenly realize "my god, so that's what that meant!" while reading one of the new ones.
As an example, in the first book Harry talks to a snake. At the time it was no big deal, right, just one magical power that Harry exibits among many. In the second book, it takes on a whole new significance.
5) Why is so much story happening in the girl's bathroom?
Because they need a secret place to make their potion, where no one else will go?
6) Why did ALL the students spontaneously show up in the hallway right after the first attack? Some internal Trouble-Alert in the school?
Coincidence. The students were being escorted in groups between classes and the dinner haul, if you remember.
7) The Powers That Be never knew that TomRiddle (their own student) grew up to be Voldemort?
Not everyone knew that Tom Riddle became Voldemort (Riddle disappeared for years after graduating, and came back very changed by his dark arts), thought Dumbledore and some others certainly did. However, they didn't know that Tom Riddle had anything to do with the problems the school was having. Only Ginny and Harry knew that, from reading the diary.
8) They never thought to look at the big piece of paper crumpled up in Hermione's hand?!
Maybe they didn't see it. They were a bit preoccupied with death threats and ancient terrors to be searching a girl for clues. The fact that she was petrified was clue enough.
9) Something smacked me as wrong about "I am Lord Voldemort" being created from his Muggle name, and I can't put my finger on it.
Suit yourself. Personally I think it's brilliant. Try it, it works. Tom Marvolo Riddle.
10) Harry and Ron were uncharacteristically aggressive with Lockhart. They actually pushed a grown adult male BACK? Then pushed him down the open well that they didn't know what the bottom was?
Further, WHY would Lockhart have been frightened in any way by being 'guarded' by Ron Weasely and his broken wand pointing at him?
By that point both Harry and Ron believed Lockhart to be a vainglorious idiot, so were hostile with him. Ron has a bit of a nasty streak.
I'd be
more frightened of Ron holding a broken wand than Ron holding an intact one. There's no way to predict how it's going to react.
a) I didn't like Harry dropping his wand while looking on the girl - too stupid, and he'd be unlikely to drop the only thing that makes him different from a normal little kid.
Perhaps, but not definitely. He was going to help Ginny, and probably just put it down, thinking he'd be able to pick it up at the least sign of trouble.
b) Speaking of just being a Muggle, it was quite insulting to the viewer (IMO) to have the entire film's drama resolved because a little kid kills the Basilisk. There is NO WAY a normal kid could kill this monster that frightened generations of powerful mages.
Remember that in the book the Basilisk isn't nearly as huge, and Harry was given the sword of a legendary hero. Also bear in mind that mages were afraid of the basislisk because of it's gaze, not neccessarily its physical prowess.
c) The Phoenix conveniently showing up and blinding the Basilisk.
Another example of Deus-ex-Machina in the story.
d) The Pheonix's tears (?!) healing Harry from certain death - another deus ex machina.
These are set up much better in the book, though I can't quite explain how.
12) This whole concept of Voldemort creating a diary which "contains his 16 year old self" is problematic.
If he can create a diary that could take over any kid and make him live again, than he effectively can never be destroyed.
BTW: HOW did the girl get taken over by the power of Voldemort, yet somehow escape the power to throw the book away so Harry could find it?
The domination was intermittent. The diary wasn't intended as a resurrection device, but as a simple diary or guide. Voldemort believed they he could never be destroyed, with good reason, so didn't feel the need for such little devices.