Before I start with this review I should make it clear that it's been a while since I've read the book, and I'm a bit fuzzy on the details of the events. There are also some minor spoilers for anyone who hasn't read the book.
So this movie was definitely a lot better than the first movie. It was much truer to the book, albeit some changes and differences (though these were much more manageable than in the first PJO film).
First, here are the good things, or at least the things I liked about the movie. Grover was still fantastic and funny. The entire scene with Hermes was great, particularly the Firefly reference. Mr. D was hilarious and very well done. I could definitely see the similarities between Mr. D in the movies and in the books. The taxi cab was very well done, and I thought it was a well-paced scene. I'm also fairly satisfied with the way they brought Luke back, and Jake Abel is greater than ever. He felt a lot colder and resentful in this movie, and I thought it was very well done. Additionally, one of my favorite scenes was the oracle scene, even though it's a bit off. It was more of the way they presented it that made an impression on me. Lastly, the ending set up The Titan's Curse really well, and I believe it was pretty spot on.
Now, the not-so-good aspects...Firstly, Annabeth is still an extremely flat character. She doesn't seem unique or different from the other background characters other than the fact that she's with Percy and Grover. She isn't shown to be the same Annabeth we know and love in the books. She's not as clever, witty, or just as personable as she should be. The beginning voice-over was also a bit strange, and it felt really awkward. The scene with Kronos was also really weird, and it was one of the scenes that made me want to hit myself in the head because it was so far from the books (I think...I'm relying on what my sister remembers, so my apologies if I'm wrong). And lastly, I was just really confused about why Silena was apparently on the yacht with Luke and his "crew." I'm hoping that they don't mess up her story-line.
And there were so many things about this movie that I'm neutral on, or at least that I'm unsure about at the moment. One is Clarisse. While I think she's really well written and is snarky and arrogant without being overbearing, she's just not the Clarisse from the books. She's too pretty and almost too nice. BUT she's just very well done in the movies, and I enjoy her as a character, so I'm not sure. There are three other characters I'm not sure of yet. One is Tyson. I liked him in the movie, but he didn't make a huge impression. You could see the innocence and child-like side of him at times, but I'm not sure how I feel about him yet. Another is the new Chiron. I don't think he's bad at all, but I also quite liked the previous Chiron. I don't think I've seen enough of him to really judge, but I'm leaning towards really liking him. And the last character I'm definitely not sure about is Thalia, whose name I am still convinced is pronounced with the 'h.' I didn't like her in the books, and from the two minutes we saw her, she wasn't as snarky, BUT I can see her being that way. Given she's a character I didn't like in the books, that might influence my view on her later on, but I'm holding off judgement until at least Titan's Curse.
Before I get to the end, I just want to mention the pacing a bit. It actually wasn't that bad. I think that the middle slowed down a bit, but not to the point where you were getting bored. The very, very end was also a bit slow, but given that it's the end, it wasn't that bad and it set up the next movie well, so.
And on a last and separate note, while the wedding dress scene was okay, it didn't have the same impact or hilarity as it did in the books, and I was really looking forward to the Circe scene, which they changed into Circeland. It's not a big deal and doesn't change much, but I really wanted to see Percy turned into a guinea pig, and I think it would have been a great time to see Annabeth on her own (if I'm recalling the book correctly).
All in all, this was a major step up from the first movie, but there was still quite a bit that could have been improved on. I actually am excited to see the next movie, especially if they continue to improve them.