I understand that the movie can not be exactly like the book, but they changed so many things and added things that weren't even relevant (burning down the Burrow). Not having the fight scene at the end was a big letdown as well. If you haven't read the book, it will be very difficult to underatnd some parts. There are some things that they didn't even explain (the Half-Blood Prince issue, which is the name of the book! They didn't even explain why Snape called himself that) I left the theatre very disappointed!