I hate to say it, but I'm a bit bored, and I haven't even been listening to this for very long. I wonder if it would be better with a different narrator? I like the author's voice, but apparently I've been spoiled by actor-narrators.
And I'm confused about how time travel works in this. At times, it's indicated that the timeline protects itself - time travelers couldn't change things if they tried, because they'd be prevented from doing so by the universe, possibly at the cost of their own lives. At other times, characters say things that indicate that time travelers could, in fact, have a disastrous effect on the timeline if they're not careful. So which is it?