The movie as good, though I would request that you read the book. The movie covered only the first half of the book and did as good of a job with it as they could. The second half of the book deals with Bastian in Fantasia (or Fantastica as it is in the book), but the second movie has nothing to do with this.
Interestingly, Atreyu was supposed to have green skin, but the make up they wanted to use in the movie looked terrible, so they decided against using it.
They are planning a remake of the book, but things are so much in the air, I don't know when or if they are going to pull it off.
MrBob