Considering this is the last book in the series, I believe a full review is in order. I started this series when I was a middle schooler in seventh grade and had to patiently wait for each book release. Now that I am a freshman in high school, I can see how I have outgrown the target audience. Even so, I can't say I was ever disappointed with the series.
This series is for young adults, but safe for younger kids as well. Unlike most YA novels, there is no unsuitable themes or elements, making the books appropriate for younger middle school kids, along with the usual YA audience.
The first four books and authors were enjoyable in my first read. Now that time has passed and I have reread all of them, they are still as enjoyable now as they were then. When reading the last book in the series, Liferaft, I was not disappointed with the writing. I can imagine it was difficult, as a new author of the story, to wrap up an entire five-book series that she had no hand in writing previously.
With this being said, the end was not what I was expecting.
In my theories, I thought the kids were somehow chosen by a team of scientists or higher beings to be put through a series of rigorous testing. Through the whole series, I imagined a Hunger Games x Maze Runner plot, with these characters going through an experiment of some sort.
However, with the introduction of the alien, I was shocked and a little doubtful. I had a difficult time accepting the explanation of the rift. Supposedly, the biomes were created due to an alien crash landing in the artic. Only one extraterrestrial survived, but the intelligent technology of the ship created a "copy" of the alien's home planet all around the ship. Over hundreds of years, this environment flourished and protected the ship from any threat or danger in the form of robots. However, the ship also seeks intelligent life to repair itself. So, that is why the kids were chosen and survived. But, since the aircraft was meant to seek help but also protect itself from intruders, the two variables opposed one another, creating a deadly combination of alien technology. All of these explanations given to the reader make coherent sense, even though it is not exactly the resolution I wanted or expected. The wrap-up seemed hasty. I wish the book was lengthened or another was written describing the alien, its home, its intent, and a fuller, detailed explanation of the rift itself. I can't seem to understand why all of the characters were chosen. The ship seemed fairly easy to repair considering the robots and mites could have done it all along. The only thing the kids really did was wake up the alien. I think another book describing the technology of the ship and having the kids repair it would be much more satisfactory. Even so, I feel like so much was condensed and glazed over. I understand the author trying to cut out unnecessary detail to fit all the new information into one book, but if you do not have the intent to write another book, at the very least, you can give a sufficient explanation of the rift which answers all the reader's questions from the previous books. I do not want to seem like I have so many bad things to say about this book. I did love the amount of Anna chapters, seeing she is my favorite character and I felt she did not get enough time in the rest of the series. I really do enjoy the series as a whole, but I wish more time was spent on the explanation and resolution of the story. All in all, these books will always be a part of my childhood and youth that I spent much time on. Taking all of this into account, I would in fact recommend this series.