I played this game on my stream (link below if you are curious) and we enjoyed the game. It's a riff on the "Annihilation" theme and it is not the first solo TTRPG to do so. However, unlike a game such as "Exclusion Zone Botanist", "Chiron's Doom" is much more flexible in how it applies the narrative concept of a doomed team marching towards a mysterious but ruinous phenomenon. The game includes three of what might be called "Adventure Modules" in the back that demonstrate this genre-flexibility. They range from a D&D/Dark Souls setting to a Retro Sci-Fi Aliens type setting. The game has the foresight to grasp that "team of curious people vs. massive weird monument" is a strong enough premise to be tied to any genre's window-dressing the player prefers.
The mechanics are where it really shines, though. I should say, up front, this is a story-telling game, full stop. There are no resources to manage, no levels to gain, no stats to grow, and--well, no stats at all, actually. This isn't a good or bad thing, it just depends on your expectations. Rather, you should be aware the only mechanic is card drawing to get prompts and then decide if that interests you. However, within the confines of that simple prompt system, the mechanics are a shifting probability system that creates the effect of a calm growing into disastrous chaos.
The game has you build a small deck of prompts that are mostly populated by cards that help unravel the mystery of the monument. However, within that starting deck, you also place a few trigger cards that--when pulled--require you shuffle into that main deck a new deck of cards associated to prompts for problems or disasters. This means, as the game goes, your deck starts with mostly just peaceful exploration but eventually devolves into mostly in-fighting and death. This is exactly how "Annihilation" style stories unfold and I find this system to be very clever for using shifting probabilities to preserve that narrative momentum.
Overall, the game has great art, effective prompts that are not too restraining or abstract, a clever take on the card prompt concept, and is one of the only genre-flexible takes on the "Annihilation" TTRPG. It also tutorializes you as you play--rather than expecting mastery from merely reading rules ahead of play. It's clearly written by someone who is an effective communicator with a clear grasp of their own game, in other words. (It's also clearly been through an editor.) The drawbacks are just that it's only a narrative system--which is only going to be a drawback if you expected a more crunchy mechanical survival-style game. I look forward to returning to the game at some point and think it earns its price-point in entertainment and quality.