All I can say is that I was entertained, in a popcorn sort of way.
Nowhere came Old Man’s War close to fulfilling expectations, raised by all these kudos it received. There’s one terrific premise which, quite unexpectedly, branches out later in the book, bundled with another nice surprise.
But that’s basically it. Character development is, like, nil—and there aren’t any noticeable “characters” to begin with. Which is a bit odd for seventy-something year old protagonists. Moreover, Old Man’s War’s plot is formulaic and predictable to an almost embarrassing degree. It’s not that Scalzi wouldn’t notice—on the contrary. He goes to great lengths to deflect it in a kind of self-conscious, postmodernist way (I’m a proud postmodernist myself, so that’s not a criticism per se), letting his characters, just in time, voice the déjà vus and objections he correctly presumes to have arisen in the reader’s mind. Which is certainly clever, but it only takes you so far. As the story goes on and the time goes by, all the predictable parts are indeed fulfilled, often so heavy-handedly that it makes you groan. (As soon as you arrive at the equivalent to Parris Island, prepare for the worst in that regard.)
From then on, John Scalzi manages to drill, like your friendly-neighborhood popcorn action movie directed by Michael Bay, any surviving traces of plausibility right into the ground.
Then, there are two narrative choices that are especially annoying.[Note: Here Be Spoilers.]
To start with, the utterly inexperienced protagonist (a former, what, copywriter?) has unfailingly the right ideas and does the right things at the right moments, which gets him raised from corporal to captain in no time. But when you look at these “right ideas” real hard, and the marvelous actions the hero performs, they reveal themselves to be rather trivial and, from a narrative perspective, curiously unimaginative. Now wait—maybe an overlooked case of an “unreliable narrator”? But no. As soon as he becomes the first soldier ever to gain the grudging respect of the over-robust drill sergeant, you will think the operating power of the word “tacky” has increased tenfold while you weren’t looking.
Next, within the context of utterly interchangeable, modular murder-destroy-kill rampages, the only person who voices doubt and tries to inject some diplomacy into the carnage is among the most disagreeable characters in the whole novel. But the clever trick mentioned above is played again: after the disagreeable diplomat’s messy demise everybody has been waiting for, another, and much more likable, character voices the reader’s thoughts that at least some kind of diplomacy mightn’t be that ludicrous after all, even if that other character’s efforts had been gross and stupid. But then, this more likable character dies shortly thereafter in even more gruesome fashion, which buries the “diplomacy” motif for good. What then? Oh yes: more hack and slay ensues.
If you let Old Man’s War sink in for a week or so, even the perceived popcorn value fades away in favor of a nagging feeling that you might just have followed some editorially polished Gary Stu through the scripted game course of a future Call of Duty franchise.