An interesting twist on the more traditional post-apocalyptic "a deadly catastrophe wipes off humanity, only a few hundreds/thousands survive"... because this time, the survivors are mostly the ones who were responsible for said catastrophe (and this isn't a spoiler: we learn about it in the first couple of chapters). We're clearly given both sides here: that of the "poor" human survivors, and that of the group who engineered everything, and was thus organised enough beforehand to be able to breeze through the aftermath.
I liked how the story made me question a lot of things. What we take for granted. The reasons behind the decision of the "bad guys". How some of them may not be so far away from humanity as they like ot think. I suspect the latter aspect will be explored more in the next installment, or at least I hope so, as it's something I found quite intriguing.
On the downside, the writing was sometimes a little too dry, and I found it hard to connect with the characters, which in turn made it harder to actually care for them. For quite a few chapters, we see them in their mundane lives, or going through the apocalypse, but mostly I wouldn't feel very invested in them. I also thought part of the explanation, given throughout the second half of the novel, tended to veer into info-dump territory (just a couple of times, fortunately). The setting also makes up for bleak prospects for the human race—but then, it depends on whether one wants to read a story full of hope in the wake of adversity, or indeed read something about a dark future, in which case The Cleansing definitely delivers.