Enjoyed the plot and storyline, but the female characters fell flat for me--I wish the author had spent more time developing them. In addition Tom, the narrator/protagonist, is written in a bro-like, off-putting way, but I saw this as an intentional choice by the author and was willing to roll with it to see where the story went.
I enjoyed seeing the detailed alternate reality that Mastai imagined, and was interested enough to follow the novel through despite the character issues. When reading about the book, I learned that Mastai wrote this story, at least in part, to deal with his own mother's death; what would life look like if she had lived? Major life events have a way of changing us and altering our life's path, which is one of the key concepts that keeps me coming back to the time travel genre; I appreciate that he used this novel to explore that, and hope that the process brought some closure.
Ultimately, I think this book does a good job with the concept. That said, I'd love to re-read another version of this with a more thorough edit and more realistic/balanced characters. Perhaps in an alternate timeline? :D