Harry Potter:

Prevented Voldemort from taking possession of the Philosophers Stone

Defeated the Basilisk

Saved Sirius Black from going to Azkaban and Saved an innocent Hippogriff

Duelled Voldemort deflecting most of his spells and escaping

Duelled Voldemort and Most of his Death eaters with the company of some of his school friends and the Order of the Phoenix

Destroyed some 1 horcrux with Dumbledore

Killed Voldemort

Married Ginny and had three kids

When Harry and Voldemort duelled, their wands, which share a core of a feather from the same phoenix, were linked in the Priori Incantatem effect.

The were never tested. There were no decisive battleship fleet actions fought during WWI. Only battlecruisers and cruisers duelled heavily against each other.

No.

The reason he comes in possesion with the Elder Wand is because Dumbledore duelled (and won) a battle with Grindelwald, whom at the time was in possession of the Elder Wand. (Grindelwald stole it from Gregoravitch- or something like that, a wandmaker)

I have heard that it's because they kinda lacked funds... Even if its just book 1, think on the bright side. It will be better since if the directors had to compress all books in only 100 minutes, many essential parts of the movie will be lost. :D I especially didn't like it when the movie did not include when katara duelled with Aang's waterbending teacher.