If all self published books were as tightly written and edited as Zero Sum Game, I’d fill my kindle with SPAs.
This was a great thriller with some very interesting characters. The main protagonist, Cas Russell, is a mathematical genius in her 20s with some definite character flaws. Not cute flaws, but serious ones - an inability to understand or connect with most people and a very hyper sense of survival with ‘kill ‘em all’ being her first defense against anyone threatening her.
Oh - that math genius bit? Very useful because she can see and factor vectors/trajectories/consequences of anything around her in a split second, and can use that knowledge to dodge or manipulate objects to avoid or mitigate the effects of, well, even bullets at time. Is it realistic? I have no idea, but it sounded reasonable, and since I totally suck at spatial anything, I bought it. Seriously, any type of fight scene I mostly glaze over, whether swordplay, battles, space fighters, because I’m clueless when it comes to that sort of thing, so I just enjoyed the idea of someone able to factor all that intricate math to their advantage.