"Strong premise & character descend into melodrama"
The book sets a great atmosphere and the protagonist is initially captivating. The narrator does a good job and the book despite it's flaws is entertaining until it becomes laughable in the end. A fitting description might be Terminator melts into Romancing the Stone.
The flaws:
The book repeatedly pulls it's punches. The lead is always "about" to get violent, but keeps warning people not to mess with her instead. The action takes a nose-dive while the protagonists wrestles with school-girlish issues of love. All but one of the potential villains have less than a page of character development in the entire book making them irrelevant to the reader. Despite the title, it is never demonstrated that the main character has any particular ability to obtain or analyze information. Her only ability in this regard seems to be that she grew up in Africa and knows the lingo. To add insult to injury the character to be rescued becomes an unimportant afterthought and the main character decides that embarrassment might be punishment enough for the people who tried to kill her and her friends.
The bottom line is that the author set out to create a Lisbeth Salander like character with no idea of what motivates such a character and little idea of what the genre expects. The extreme weakness of the protagonist at the end (i.e. indecisive, illogical, passive, and naive) would make Jack Bauer and Mitch Rapp hurl. And back to pulling punches, the author blends three different endings together instead of choosing a solid one. It's akin to "It's okay that I let my son's killer go free, because he died in a car accident a few weeks later."