So after Neville killed the Snake really Voldomort just died after that in the books? Because that would make sense, the snake died, Voldomort cried out in pain and yet him and Harry shot another stream of magic at each other and Harry won, but it didn't look like it was from Harry's wand because Voldomort just dropped his wand, paused then slowly started to disintegrate. The movie made it look like Harry killed him, kind of.

In the book V and the death eaters make Hagrid carry Harry to the front of the school where most of the other force were, they lay him on the ground and there's a bit of gloating while V holds them still and quiet (though he is having trouble making his spells last) Neville breaks ranks to try attack V but is slammed to the ground (magically) then there is some more talking and V magics the sorting hat down from the headmasters office and puts it on Neville's head before setting fire to it. At that moment Grawp and the centaurs make their presence known which was when the actual battle began. During the distraction Harry got up from pretending to be dead and covered himself in the cloak, and Neville got the Gryffindor sword from the hat (still on fire) and killed Nagini.

V screamed, Harry (invisible) put a sheild spell in front of Neville in case V tried to attack (doesn't mention if he actually did) and Hagrid then noticed Harry had dissappeared. The battle was now raging with thestrals, Grawp, Buckbeak, centaurs, witches and wizards vs. other giants and the death eaters, and most of the witches and wizards were forced back into the castle. The important people ended up in the great hall (Harry protecting people when he could against death eaters and the house elves joined in) Various duels break out inc. Mrs Weasley vs. Bellatrix... when Bellatrix falls Harry reveals himself to protect Mrs Weasley against V's retaliation.

Then Harry and V circle each other for a few pages with Harry explaining stuff about wand lore and hallows and everything before they each use their signature spells. V's wand won't work against Harry's though so as the spells meet in the middle his rebounds and kills him. (In both film and book Harry casts Expelliarmus, which is not a killing spell, so it is Voldemort who kills himself either way)

Ok so it was completely different then the book...lol as usual. Oh well that explanation does clear things up for me, thanks.

Well it's an action film, they have to make it exciting to watch. When this kind of thing (epic battles, not magic) happens in real life the actual "exciting" parts don't normally last very long, but to those who are part of the battle they seem to last a long time (the mind stretches those parts out because so much happens at once) With the film medium it would be very difficult to make it seem like an epic battle if it didn't even last 5 minutes (which is probably about the amount of time it takes in the book while Harry is invisible)

Books have the unique ability to have time move as fast or slow as needed. Whenever it gets more descriptive about a particular scene, it is kind of like the time-dilation effect the mind goes through when something exciting is happening. Films can skip sections to a new scene, and maybe have a time-lapse portion of a natural process to show time passing (fade between autumn and winter for example) but each scene has to be at life speed.