By now, the redshirt has become a cliche: the sacrificial lamb, the one who always dies, the one you don't want to be in a group. Scalzi turns the concept into a weirdly funny and meta book that takes it oddly seriously.
On the Intrepid, going on an away mission is a terrifying ordeal to the rank and file crewmen. The bridge officers (mostly) do fine, but it seems like somebody is always dying. And nobody cares. The ship takes high risk missions, that's all. The main characters, a stubbornly ragtag team of new crewmen, slowly come to accept that the problem isn't the crew, or the officers, or the missions. The problem is that another reality is intruding on their own, one where the Intrepid is the setting of a badly written science fiction series.
I listened to this book while on a car trip, and it was perfect for that. Entertaining, with engaging characters, and just enough going on to keep me interested without distracting me from my driving. But in retrospect, there are some failings that could be considered pretty serious. The lack of description. For most of the characters and, crucially, the ship itself, there's no effective description. What does the Intrepid look like? I have no idea. I just kept imagining the Enterprise-D, since that's the Trek I grew up on, but I have no idea if that was the author's intention. Also, there's a lot of "said". Nearly every dialog tag is "said", nothing else. For the most part, I could tune it out. But I know that this seriously gets on some readers' nerves, and I think it was even more obvious in an audiobook than it would have been on the page.
All of that said, is it entertaining? And yes, it absolutely is. The dialog between the characters if fantastic, especially when they aren't dwelling on the plot. And I actually really liked the codas, which extend the book by an astonishing amount. (The took up most of the last two discs.) Because a lot of the time, no thought would be given to the people left behind in the universe where Intrepid is fictional, and one character in particular really deserved it. I think this is the first thing that I've read (or listened to) by Scalzi, but it certainly won't be the last.