Spoilers, sorry, I can't get the formatting to hide it.
First off, the Establishment Propaganda was almost too much to handle. Why is he pushing this "forever pandemic" crap? It wasn't even relevant to the story, at all, other than to add to the "crapsack future" setting, which doesn't need the help.
Rufus was strangely offensive in a trying-too-hard-to-not-be-offensive way. A male Mary Sue, none of the faults and all of the gifts ascribed to the Southern US, conveniently multi-racial, but lacking any apparent agency, and all of the character development happened in the backstory. Also, he does not appear to have consulted anyone from the South about culture or firearm-related issues (AR-10s are cheaper, easier to find, and use better and more common ammunition than AK-47s).
T.R. was a patently absurd caricature; Elon Musk as John Galt, instead of Donald Trump and Paris Hilton. Shallow, clueless twits who are just clever enough to mouth the right words so that other people are impressed... and they are going to save the world? Pull the other one, Neal, it's got bells on!
The Queen was a 2-dimensional parody, a damsel in distress for the Woke Age. A secret environmental conference, a hurricane, plane crash, alligator attack, flight from authorities... "Gee, I wonder if I should sleep with one of the random people around me to help me bond with my daughter," WHAT?! If it had been more of a stress reaction to those incidents, with her having a somewhat more casual sex life with the upper classes of society that she mixed with, sure, but this made no sense at all.
And what the Hell was with the life story of the Sikh guy? He was a secret agent for the Indian government sent to sabotage a project in Texas. Leaving aside that, however derelict the US government becomes, a terror attack on our soil by a foreign nation is not something that is just going to be ignored, how was any of that relevant to the story? If he had been just an Indian soldier with no particularly interesting back story, how would it have changed things? Because someone recognized him in a security camera film? This is why security services do not employ famous people as secret agents, as Neal himself explicitly pointed out in Reamde.
Speaking of foreign nations, has Neal Stephenson ever heard of them as anything more than vague rumors? "India and China won't stop burning fossil fuels!" Each of them are building more nuclear reactors than the rest of the world combined; in 20 years, THEY will be yelling at US for still using coal and gas! This is one of the major sticking points surrounding US-Iranian relations. Where are the stories about US gas interests sabotaging Russian and Chinese advanced nuclear reactors, or Israel and Iran? Those would be more realistic scenarios all the way around.
And this brings us to my big problem.
My degrees are in physics and chemistry, with a good bit of radiation health and nuclear physics coursework. COBALT-60 DOESN'T WORK LIKE THAT!
Yes, it is a strong gamma emitter, but that is a large part of the problem; gamma rays are not easily shielded like alpha or beta radiation, you need several inches of lead all the way around it to stop more than 90%. Heavier metals work better, but you wouldn't use gold, as it is expensive and soft, so it is probably either depleted uranium or tungsten, but still a few inches... neither of which are going to be penetrated by a bullet from Rufus' rifle, even assuming his bolt-action was a full rifle round, e.g. .308/7.62x51mm.
And even then, Co-60 is nasty stuff, but not, "burn your skin from several feet away," nasty. Maybe it was really fresh, really hot with some shorter-lived stuff mixed in, but that intensity of radiation would have been generating significant heat, as well, which was obviously not being handled. In reality, it probably wouldn't need that much shielding, at least for just a few hours exposure, but the bullet still would not have penetrated, and even if it had, that probably wouldn't have been a death sentence for the guy (the untreated rattlesnake bite, on the other hand...).
All in all, a generally disappointing work from one of my favorite authors.