Is only 1-star because you can't give a 0-star.
if you didn't read the book, you won't like it, even as a standalone movie it sucks, since even if you didn't read the story you would guess who is the villain.
If you read the book, you will hate it, all characters were butchered to sexual fantasies, and failed bad, the plot was terrible and didn't make sense, and there is no sassyness from Percy, no intelligence and wisdom from Annabeth, and Grover... what the hell happened to him? I don't mind the inclusion thing, since PJO-series is all about that and I think is required to even compete for the Oscar or something, but the timid and self-doubting boy that when nervous eats things became someone that probably went to the quest to have sex, and was implicity show having sex with different girls, and even traded Ares for Persefone for more sex, was the director self-inserting into wish-fullfiliment Grover?
I bet that Craig Titley (Movie Writer) didn't even read the books, and the trailer said that was directed by the same person that directed Harry Potter - it didn't show, it was just used to to hype things.
Well, as expected of a Movie Writer whose IMDb rattings for movies never went above 5.9... and this is his best movie.