This film was handicapped by the fact the first movie strayed so far from the book. So alto of the discrepancies were do to explaining characters that were dropped from the first film like Clarisse, Mr. D, or not explaining Grover's quest.
What bothers me the most is the studio treating this as a throwaway film. This movie was barely promoted and to wait three and a half yeas to put forth a low budget effort, is disappointing.
This film for the most part tried to be faithful, unlike the first film, but I also felt it lacked some gravitas performances they got from Brosnan, Thurman, Bean, and especially Steve Coogan.
I enjoyed Fillion, but there just wasn't enough else. While the main cast does a good job, Jake Abel was just horrible, he did a good enough job in the first film, but he never seems like a threat.
I hope they can finish the series, but this film clearly is not going to do as well as the first.
Overall, I liked this movie, even with its faults, but the film is going to do little to attract new fans.