I've recently finished watching Fullmetal Alchemist and I then proceeded to watch an episode of Brotherhood before realizing, Brotherhood isn't actually a continuation of the first series. I then discovered there was a movie that tied up the loose ends at the end of the first series. Now, I want to know, what actually is Brotherhood? I've read that it's simply a version of the show that follows the manga more closely, but I haven't read the manga and I really enjoyed the first series. Will watching Brotherhood disappoint me or change my views of the ending? Could I have watched Brotherhood without having watched the first series (or at least before)? Are there any major (specific) changes that might frustrate someone who is dead-set on things happening like they did in the first series?
I know I have a lot of questions, but I hope someone can answer most of them! Thank you so much!