Stays loyal to the books in essence but I wish it followed the plot more closely - the Captain Underpants books do a great job of building up to its finale (assuming book #8 is the final book, I think there's more now). Would've been awesome if they stuck to one movie per book, but this will have to do. Also, I like that this movie is very self-aware in that it realizes the crass nature of what it's handling.