When I looked up other reviews of this game, I also saw another criticism that I don't entirely disagree with: that the underlying politics of the game is anodyne to the point of being incorrect. As the game progresses, the various peoples of the tower also learn each others' languages, and that communication ends up reducing enmity and causing unity among the peoples of the tower, with the ultimate theme being that the previous isolation and xenophobia seen throughout the tower was just from a lack of shared understanding.
I don't disagree in general that this is a reductive way of thinking about the world. Not all divisions can be healed by a shared language! After all, I'm a queer person living during an era of rising fascism, which means there are plenty of people who share my language and culture who would nonetheless love to see me and people like me dead. And I do think the game sets itself up for this criticism, since one of the peoples of the tower are the "warriors" who explicitly see the monks of the lower layer as "impure" and who have the stark fortresses and bright red banners and lines of soldiers that serve as shorthand for fascism. In the real world, the ideology of fascism has never been defeated by "reaching across the aisle" and sitting down with a warm conversation, and yet by the end of Chants of Sennaar, it took nothing more than bilingualism for the warriors and monks to put aside their differences and become friends.
But while I agree with the political point as a whole, I don't care for it as a criticism of this game in particular, for two major reasons. The first reason is that I'm willing to defend utopian themes in fiction explicitly because they doesn't take into account cynical realities. It's very, very easy—especially in modern political climates—to accumulate so much cynicism that you end up being defeatist about any attempts to improve the world. There are people who start from, "fascism as a whole cannot be defeated by conversation," and end up concluding, "no individual fascist can ever be talked down from fascism by a conversation," and that's not true! It's true that not every division can be cleared up by bringing people together, but some divisions can, and firmly asserting otherwise is, quite frankly, doing the fascists' job for them. In light of that, I think it's useful to experience some naïve utopianism from time to time, because sometimes that hopefulness can be a balm against overwhelming, paralyzing cynicism. (This is also why I still love the sometimes-corny utopianism of classic Star Trek.)
The second reason is that it's a light six-hour puzzle game. Like, come on. This is like, "I can't believe Luigi doesn't have to do suspension maintenance in between races in Mario Kart," type shit. Sometimes the realities of the world are simplified for the purposes of video games. Deal with it.