Thanks to @HarrisPS for alerting me to another title by Yeonsoo Julian Kim in Choicescript, leading directly to this review, since I already owned this game.
Undying Fortress
by Yeonsoo Julian Kim
Published Dec. 2025 - 500,000 words
Undying Fortress is a dark fantasy in a setting blending elements of European style fantasy with a fresher Asian (specifically Korean) inspired fantasy world. You play as a disgraced former student of the Imperial Academy, now making a living as part of a mercenary company. When the floating fortress that has hovered high in the sky for nearly a millennium comes crashing to earth, you are tapped by the Imperial Crown to lead an expedition inside to discover it’s secrets. What you find and what you do will determine your fate and future, as well the very survival of the kingdom and the people under your charge.
So…time to confess something. Fantasy is always a hard sell for me. Any story or game in the genre is going to face an uphill battle gaining my appreciation. It’s my own fault, because like a kid who eats so many chocolate chip cookies they get sick and ever afterward have a bout of nausea when they smell the aroma of more, I used to consume a lot of fantasy.
For about 15 years, I read nearly nothing but fantasy at a rate of 2-3 novels a week. If you do the math, I read around 2,000 fantasy novels during that time, not even counting the short stories or other fantasy media I consumed. I read great fantasy and awful fantasy and everything in-between.
“Familiarity breeds contempt” very much applies here. I grew tired of and exasperated with all the tropes, repeating elements, endless recycling of Arthurian and Tolkien themes and concepts.
All this so you know where I’m coming from in this review and future ones - for instance, the marketing for Undying Fortress leans very heavily into the fact the player has a magical family sword with a name, handed down through generations. While that might have been a selling point for some, it’s actually the reason I put off reading this title, even though it intrigued me enough to purchase it. I’d encountered plenty of flying citadels in fantasy, of course, but the concept of the citadel crashing down and a fantasy expedition inside was enough to get me to pull the trigger on the buy, but the magical sword bit kept it low on my reading priority list.
Though you might have some inkling as to how well I took to the actual story since I’m reviewing it just two days after @HarrisPS brought the author to my attention.
PROS:
World-building. Yeonsoo Julian Kim does my favorite thing with fantasy world-building—she lets you figure it out for yourself. You get context clues as you go along and brief natural explanations that only give you just enough to understand the current context of what’s going on. It’s up to you to piece it all together and you’re never given a giant info-dump of text about god pantheons, kingdom hierarchies and histories, or all the exact little rules of how magic works in this world. She clearly knows those things, but like good fantasy, the world-building is sub-servant to the story and gets out of the way and stays in the background.
What you can construct as the reader is a very Korean-inspired fantasy world, with sliding doors, pagodas, tiled roofs, Imperial Courts, and embroidered robes. I was visualizing something similar to the world of Avatar: The Last Airbender. On that same note, I appreciated the way Yeonsoo Julian Kim described spells and magic being used in detail, down to the material components the caster was using and the movements of their hands or body.
The fortress itself feels like a real location, loving described to such a degree that by the end of the story you really have a strong grasp of how it’s laid out and how everything fits together, as well as it’s history.
Discovering how everything fits together within the fortress, why it exists, why it was flying for all this time, and what secrets it holds, really act as a nice mystery to constantly keep driving the player forward to discover more.
Stats. Though there are nearly as many stats in Undying Fortress (14) as there were in Yeonsoo Julian Kim’s previous Choicescript game The Fog Knows Your Name (15), here they were done much better, with much less overlap of purpose or confusion on what was being tested at any given time.
It also certainly helped they were clearly and cleanly split between “Qualities” and “Skills” and all visible at a glance on one page. To be honest, I’m not entirely certain if the seven “Quality” stats are ever tested against in choices—I’m reasonably confident they only contribute to flavor text or character interactions. Mostly they serve to show the player how their character’s personality is shaping up.
The “Skills” stats each clearly have their own lanes to occupy, and even in cases where there could be some confusion (there are three different magic or casting skills), Yeonsoo Julian Kim does a great job of telegraphing the stat being checked in the choice text, so you’re never wondering which casting ability is going to be tested.
Characters. I started Undying Fortress being a rather stand-offish proper character who was a bit ‘sour grapes’ with everyone, but I was surprised by how much I warmed to practically the entire cast of characters by the end, even ones I didn’t care for based off initial impressions when I first met them.
Impressively, they nearly all had satisfying character arcs that ran throughout the entire story, even the antagonists. Yeonsoo Julian Kim does the rare thing in fantasy of making no character all good or all bad, but all looking out for their own self-interests and goals with a full spectrum of gray that makes deciding who to side with or against something that really demands thought from the player.
The game also makes a big deal about how you’re responsible for the safety of your expedition group and you really do feel yourself wanting to live up to that responsibility.
Endings. Now, I can’t say for certain, since I’ve only played through once, but it seems there is an impressive amount of variety in the endings, judging from the fact even the ending I got (which I had to choose out of multiple others) came in three very distinct variations.
The ending I got was very satisfying, since I accomplished my character’s goals, got every member of the expedition out alive, and more on top of that.
Options. Okay, sure, maybe that’s another word for ‘choices’, but, yes, I really liked them here.
It’s not many fantasy games or stories that give the protagonist a magic sword and then let the protagonist choose to never use it, or even shrug when you lose it.
I also didn’t realize how fun it could be to play a pacifist in a dangerous fantasy adventure until Yeonsoo Julian Kim gave me the option to do so in Undying Fortress. Or to look at jewels and treasure and go full archeologist mode by yelling at everyone the fantasy-world equivalent of “It belongs in a museum!”
CONS:
I really had to struggle to come up with any, but I do have one minor one.
Pacing gets a little bogged down towards the end. The pacing is great throughout much of Undying Fortress, keeping the tension and drama building at a steady pace. Even the actual ending and epilogue are nicely paced.
However—there are dramatic vignettes toward the end of the story with each of the major characters, each one serving as a sort of penultimate climax to their personal story arcs with the player.
Each of these are exciting, well-written, and with interesting choices. They are also fairly long. If I had to hazard a guess, they are each probably several thousand words. So individually, I liked them all, but back-to-back for over half a dozen characters was a lot when I was geared up for a final confrontation.
This might be because I was a victim of my own success, in that I made sure absolutely no one died and had formed fairly close relationships with everyone. Perhaps this next-to-last section of the story would have gone considerably faster for players with a higher casualty count.
It’s still a nit-pick, but a minor one. I really did enjoy each of these long sequences individually.
Final Verdict:
(10/10)
Final verdict, I would recommend Undying Fortress to anyone that enjoys fantasy stories or even just Choicescript games, as it does pretty much everything right, even to a jaded fantasy reader like myself.
I don’t give full marks lightly, as I’ve read a lot of Choicescript titles over the years and there are only a handful I can think of worthy of top marks, but this has to be one of them.
. I’m getting much better at figuring out why some tropes/writing/design choices “click” while others don’t.
vibes