Amazingly well written and thought up. There were some spelling mistakes in the epub, but they were small and didn't detract from the experience at all.The ending was a huge and pleasant surprise for me, haha, i didn't expect it one bit. I really, really hope there will be a book three! :)
The one thing that could have made this series even better would be a deeper focus on the technical side of things, or even just more content on the science and theory behind it all--it would make things a lot more interesting, more real and deep. You should maybe mention how Jay charges herself, how she replenishes her supply of chemicals for pheromones. I would also like to see Tyler converse more with Jay about her machine aspects, that would be interesting.