Hugh Howey's first Wool serial is a short piece that compels the reader to consume until satisfying finish. It reads very much like a short story, and the prospect of a series follow-up is an exciting one: we don't have to leave the world just because one story is finished.
(For more on Wool Part I, click here.)
Wool 2, then, has some big shoes to fill. While the first Wool is free, the second part of the series costs real money ($0.99, granted, but there's a big distance from $0 to there). It needs to justify its existence, engage the Wool reader for the series' long haul, and measure up to part one.
Where 1 felt like a vignette, 2 feels like a chapter in a book. Much of the structure of the story feels designed to give the reader a tour of Wool's silo world and how it works. This isn't necessarily bad; the reader gets a good look at Howey's world-building, and a better picture of why and how things happened in part 1 - but the shift from the deft interweaving of world building into plot elements (a hallmark of part 1) to more forced exposition is jarring.
The story itself is also another departure from 1; where 1 was fueled by tight plotting, 2 is a character study. Again, not necessarily a bad thing. The reader comes to know and care about the characters more this time around.
So does it measure up to part 1? No, but it doesn't let down, either. Importantly, for the readers who are newer to science fiction, 2 creates a realistic world that functions. It fleshes out the universe to create room for more stories to grow.
And yes, I'll probably just turn around and get Wool 3.