I read the books, and I loved them. I was so enthralled in the world that the author had created, and when I learned that there was going to be a movie, I was ecstatic. But when I saw it, I was severely disappointed. So many details were ignored, and I was angry that Disney had ruined my expectations. I couldn't believe how much they ignored, and it made me sad... and angry.
1. Artemis Fowl Sr. was kidnapped by the Russian Mafia and held hostage. Artemis Fowl Jr.'s mother had lost her mind, and Artemis was looking for proof of Fairies, which is a word used to describe every species in the Fairy world; there are trolls and centaurs, elves and dwarves, sprites and goblins, and pixies that are no taller than a few inches but wizz about the air in hover chairs. There is no species that is called Fairy.
2. Artemis Fowl Jr. wanted Fairy gold, not the 'Aculos', and I am fairly certain that a giant golden acorn doesn't exist in the universe Eoin Colfer created, nor is it the source of Fairy magic. Fairies do a little ritual at night to recharge their magic stores, they don't have what seems to be unlimited magic, as the movie portrays.
3. Domovoi Butler is supposed to be called "Butler" and nothing else. His first name was not known to Artemis until he was near death in "The Eternity Code".
4. Commander Root is supposed to be a freaking man, not a woman. The very fact that they changed this detail angered me. Commander Root is also supposed to be angry at certain points, which earned him the nickname "Julius Beet Root", because his face became so red when he was in a rage.
5. Opal Kopoi is no taller than a few inches, and wasn't even introduced into the series until after the first book.
These factors, and much more besides, truly ruined the movie for me. If you ask me, I would say that the world was waiting for this movie, and it was sorely disappointed in the failure on Disney's part.