If I was to sum up Enclave in one word, it would be "anemic."
That might be all I needed to leave my thoughts on this work, but simply saying a work is "anemic" isn't particularly informative, so while I don't have much to say about this work, here's my thoughts:
-The protagonist deals with Christine who lives in Safetown - a walled community replete with a wall (that the cover art makes look like something out of Super Mario Land for some reason 0_0), that's also replete with turrets, drones, and security. I'll deal with the worldbuilding elements later, but Christine is...alright, Christine kind of sucks. There's a saying in writing that states "give your character weaknesses, don't make them weak." Of course, another saying in writing is "you need to know the rules [of writing] so you know when you can break them," but reading this, the first saying comes to mind.
Christine is a character that's reactive for 90% of the novel. Things happen to her, there's very little she actually does for herself. Being as generous as possible, I could say that Christine gets as far as she does because of the kindness of strangers, which does tie into one of the book's themes, but even if that arguably works thematically, it still doesn't work on the level of character. While that's arguably damning enough, Christine's romance with Sienna has got to be one of the poorest romances I've ever seen in fiction. EVER. Basically, it can be summed up as:
1: Christine sees Sienna the first time, is attracted to her.
2: Christine sees Sienna the second time, they end up kissing passionately.
3: Christine pines for Sienna for 80% of the book
4: Christine reunites with Sienna, turns out Sienna loves her too for vaguely defined reasons.
5: Cut forward about a year, they're engaged
I, um, what? I was expecting through the novel that Christine's love would be unrequited, because interacting twice and having a fling on the second go is rarely the basis for a long-term relationship but no, Sienna truly loves Christine, despite only having interacted with her a handful of times.
It's made even worse because in their interactions, it's less that the characters are talking "at" each other, not "with" each other. It doesn't help that none of the interactions up to point 4 above have any real dialogue, and when we reach Point 4, Sienna's reasons for loving Christine are "I like you because you're not like the other residents of Safetown" (which is technically true, but Sienna has no real way of knowing that beyond Christine not being terrible), and "I know you're racist, but I love you anyway" (even though Christine's never actually done or said anything of the sort), and apparently that's enough to make Sienna love her because...reasons?
-The actual writing of the book is fairly anemic as well. It isn't uncommon for a chapter to be just a few pages - written in the style of snapshots, but not a snapshot style of story. I already mentioned that the interactions between Sienna and Christine felt like characters talking "at" rather than "with" each other, and this is true for a lot of the novel. As in, a character will come in, state what needs to be said, and move on. While this works at times (e.g. Christine is emotionally estranged from the rest of her family, so this kind of dialogue makes sense in these cases), it doesn't work as well for the rest of the novel. For instance, early on, an Agent (capital a Agent, as in...the Matrix? Can't deny I spotted the similarity) states that Christine has been exiled from Safetown, but the interaction is just a few paragraphs. The Agent says what needs to be said, then moves on. Christine finds a character outside the Wall, then moves on. Christine finds someone in Melborne who helps her, then moves on. Rinse and repeat.
-The worldbuilding of the novel is a mixed bag. Having read both Terra Nullius and The Old Lie, and now this one, I've noticed a trend with Coleman and that's that worldbuilding is really her Achilles heel. Terra Nullius suffered from enough plotholes to sink a starship. The Old Lie's setting suffered from being vaguely defined, and certain events that make no logistical sense. Enclave arguably has the tightest worldbuilding of the three, but that's not because the worldbuilding is particularly good, it's because it simply has fewer plotholes.
Here's what we know about the setting of the work. Enclave takes place in an indeterminate point in the future - late 21st or early 22nd century by my estimate, though the actual year is academic, granted. Christine and her family live in Safetown, which is a walled (literally) community that promises freedom from the outside world. We learn very little about the outside world, but the Enclave's Safetynet does allow us some peaks at the world. Apparently the US has annexed parts of Mexico, Mexico is taking things up with the United Nations, there's still war in the Middle East, and really, that's about it. Also, the world's grown hotter. You can guess, correctly, that Earth is being ravaged by climate change, though we learn very little about what I said above, apart from some islands being swallowed by the rising seas. However, Safetown's control on information is so absolute that despite being located off the coast of Australia, Christine has never even heard of Australia. So, the rulers of Safetown allow information on other countries to get through, but not the country they're located right next to? I'm not saying that's impossible, but it does strain credulity, and raises the question of just how much the average person in Safetown knows about the wider world. We can make a few guesses, but as it's established that Safetown survives as a de facto city state mainly through financial services, clearly there has to be some engagement on some level with the wider economy.
Regardless, we do learn more. While it's never really gone into in detail, we learn that similar enclaves exist (presumably in Australia, it doesn't really specify whether this is a global phenomeon or not) where people have grouped together based on financial, religious, and/or ethnic affilitation. While it's not stated, we can also infer that because of climate breakdown, certain people have grouped together. I actually can't fault this idea in of itself - certainly there's a precedent for this in the real world. However, it's left vague as to why Australia (the country) tolerates this, or whether Australia (as a country) technically exists anymore. We know that when Safetown was founded, the ADF still clearly exists, but by the timeframe of the novel, there's no mention of a federal government. Melbourne (more on that later) is presented as a 'good' type of enclave, almost (diverse, solarpunk, etc.), but taking things as writ, we're kind of left to assume that the entire continent has 'good' enclaves and 'bad' enclaves. I wouldn't mind so much if the novel hadn't already established that countries and the UN still clearly exist (and if they don't exist, there's no realization as such). One of the moments that caught my interest was when Christine gains access to information in Melbourne, but only a paragraph or two is spent on it. Similar to The Old Lie, it's not just that certain information is never presented to the reader, it's that the characters themselves seem so uninterested in at least asking basic questions.
-Concerning theme, I get what the novel is saying, and on that note, it more or less succeeds. If we go with the paradigm that places like Safetown are "bad enclaves," and places like Melbourne are "good enclaves," then the novel does put in the legwork to justify why that's the case, both on the level of worldbuilding and theme. On the latter, the core theme that prejudice is ultimately self-defeating, because even on a purely utilitarian level, places like Safetown are denying themselves human capital through ills like racism and homophobia, whereas a more welcoming place like Melbourne can succeed because it's more welcoming of all peoples, hence why it can thrive. Some of this is outright text, where it's established that places like Safetown are behind places like Melbourne in terms of technology and lifespan. Similar to the idea of enclaves as a whole, this idea has grounding in real life - dictatorships fare worse than democracies on the HDI for instance.
Still, on the level of worldbuilding, this doesn't work as well. As I said, the book leaves things poorly defined as to what the geo-political situation actually is, and Melbourne is stated to be the best city in the world (at least in terms of climate action) because...the people decided to? Considering Australia's been a laggard in this area for the past few decades, assuming that the world here is the same as our own (and there's nothing to suggest it isn't), there's no real legwork as to how or why this happened. I'm reminded of a line in 1984, namely "I understand how, I do not understand why," only for the answer as to "how" to come later. In Enclave, I, the reader, can only say "I understand why, I do not understand how," only the answer as to "how" is never really explained or explored. Similar to Coleman's other works, certain facets of the world are presented "as is," because the story demands them to be.
So, no. I can't give this book anything more than 3 stars. Enclave fits into dystopian sci-fi well enough, but when I think of the all time greats of the genre (e.g. 1984 and Brave New World), those books succeeded on every level, from characters, to worldbuilding, to themes. Enclave only really succeeds on the level of theme. Everything else is lacking.