A few Spoiler Alerts for below.
The Common Sense Media assessment is incorrect regarding adults in the book. At no time in the book does an adult directly harm a child. The teenage boys do, in fact, battle monsters (not people) that are semi-mechanical, hairy slugs with knives and spikes, but there are ZERO scenes where there are "adults murdering children".
There are four main violent scenes, and in only two does anyone die.
The first scene is at the beginning, where one boy spears another. The boy doesn't die. In the second scene, a boy jumps into a slug monster and is carried away by it, presumably to his death. He doesn't die, either. Other references to killing are obscure and described as boys being "taken" by a monster, presumably to his death, but it's not certain. The boys are NOT aware of who is responsible for their predicament (which is actually one of the mysteries the boys want to solve), and only discover the truth in the last 20 or so pages. The third scene is in the final confrontation in a battle with the slug monsters, where the violence is obliquely described as bloody smears, screams, and that sort of language - it's not described in detail. The final, climactic scene is probably the worst, where one boy throws a knife at another, and it is described fairly but not gratuitously, an adult scientist is shot (by another adult), and a zombie-like adult is run over by a bus (driven by an adult).
Ultimately, adult scientists are controlling the experiment, so they certainly are responsible for the deaths, but via a computer system and what we can assume are robots, so the description of "adults murdering children" may be true technically, but it is at a GREAT distance and certainly "out of sight", since the only way the adults can see the children is through the eyes of a six-legged lizard robot (again, we presume, since the author doesn't explicitly say that the adult scientists of the experiment can see the boys); in that respect it is very much like The Hunger Games.
"Some of the teens in the Maze go insane from the fear" - makes me wonder if the writer of this sentence read the book - the boys who go insane are injected (stung) with something by the slug monsters.
The adults in the book are ultimately untrustworthy, even the ostensibly good ones, and it's unclear whether they are bad or good - I suspect the subsequent sequels reveal that. Other than that, the book is derivative and full of cliches, making it inadvertently funny at some points (like the description of the Grievers), so it would be perfect for a movie or TV series. Also the shucking language is distracting, I mean WTS?
It's a bleak setting for a bleak story that ends bleakly - I rated it as 3 stars, because there isn't a choice for Not Terrible.