Very short review:
Recommended because it’s an enjoyable experience that manages to be both calming and thought-provoking. And it’s not overly long, so it does not get boring despite a certain lack of interactivity.
Longer version:
(Note: contains what might be considered fairly mild spoilers, not for the plot, but for the general topics of the game.)
Faerethia is a choice-based work of science-fiction which partly reads like a philosophy essay.
As I was getting immersed in the very idyllic beginning and enjoying the calm and beautiful music, I was wondering whether the game would soon “pull the rug” out from under me.
While I leave it to the reader to find that out, I can note without spoiling too much that the environment indeed changes several times throughout the story. This is also indicated in the visual presentation, as the game changes the font type and colour, as well as the background colour.
In the beginning, the tone is sometimes a bit lofty and lacking in concreteness, but that is appropriate for those passages. The author is clearly capable of creating a variety of styles and atmospheres through his writing, and I enjoyed seeing a peaceful countryside, a stressed-out character in a messy academic office, a send-up of corporate advertising prose, and other scenes.
The game’s choices do not really influence the plot, they mostly just serve to structure the delivery of the text, or to present slightly different aspects of the content.
In longer or less well-written games, this might have the potential to annoy me, but I don’t see it as a big problem here.
In a way, it even seems fitting, in the sense that we are free to do a variety of things that flow causally from the protagonist’s character and motivations, since the author seems to take a compatibilist stance on the free will & determinism issue.
Faerethia touches on a lot of philosophical topics. The central one is something akin to a transhumanist conception of the future.
On my reading of the work, the author endorses that idea, but he is not altogether naively propounding a tech-utopia. Several (fittingly dark) passages show a clear awareness of the social, political and economic problems that humanity is facing.
The game provides food for thought, and one wishes that it would go into more depth sometimes:
“All personal desire had to be set aside, allowing the individual good to be subsumed in the universal. The recognition that they were in fact the same, had always been the same, did not come quickly or easily.”
Indeed, the question how to reconcile (let alone identify) the individual good with the universal good has of course occupied philosophers for a very long time, see Rousseau or Kant, for example (and countless others).
Part of the story’s answer presumably comes in form of a theory of personal identity that takes the form of a four-dimensionalist stage-theory and also reminded me a lot of Derek Parfit’s account, see a pertinent passage from Parfit’s “Reasons and Persons” further below. This then ties in with the game’s utilitarian outlook.
In line with its general hedonistic tendency, the story also offers some consolation on the subject of Death, similar to the Epicureans’ views.
Critics might adduce something like Robert Nozick’s Experience Machine argument, casting doubt on the desirability of the scenario. This would also be interesting to explore further, along with the other points mentioned above.
It’s cool to see such subjects coming up in IF (even if briefly), and I’m grateful to the author.
(p.s.: Sorry for dumping so many links above, but maybe they will be helpful for people who would like to delve deeper into the topics presented by the story. 
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I’ll close with a passage from Derek Parfit’s “Reasons and Persons”:
“My life seemed like a glass tunnel, through which I was moving faster every year, and at the end of which there was darkness. When I changed my view, the walls of my glass tunnel disappeared. I now live in the open air. There is still a difference between my life and the lives of other people. But the difference is less. Other people are closer. I am less concerned about the rest of my own life, and more concerned about the lives of others.” (p. 281)
“And, as I have said, I care less about my death. This is merely the fact that, after a certain time, none of the experiences that will occur will be related, in certain ways, to my present experiences. Can this matter all that much?” (p. 282)