This Статья is to point out the differences between the Book Эрагон and the Film Eragon, which was a great disappointment to many fans, including me. So here we go, my information is from the InheriWiki.
Book- Эрагон had brown hair and brown eyes. Film- Эрагон had blonde hair and blue eyes.
Book- Эрагон was fifteen at the start of the story. Film- Эрагон was seventeen at the start of the story.
Book- The gedwëy ignasia mark is a круг and glows silver if the Dragon Rider uses a spell или reaches for magic. Film- The gedwëy ignasia is in the shape of an 'e'.