First off: MAJOR plot spoilers but no puzzle solutions. That said, unless you subscribe to this specific theory, the plot doesn't have a whole lot of weight or emotional depth, at least from where I'm viewing it. It's a silly game and that's absolutely fine. I bought it because I wanted six or seven hours of mashing every single object I picked up into every single interactable location I came across, and it did indeed give me that, plus some rather ingenious brainteasers (triangle/circle lock puzzle, I'm looking at you).
But. Um. So. There's a weird thing about this. I played this with a group of people, and we all found it rather silly, and some of the Moon Logic Puzzles are frustrating, but we cheated, because the point was to have fun, and we got about halfway through (I just finished it on my own).
And.... about at the point where we discovered the main character's name was Umang and he looked like a white guy with a vacant stare, and that the "Sacred Rings" looked exactly like a gyroscopic physics toy, we collectively decided to stop taking the game seriously, and we made it our headcanon that he was, in fact, a patient at a mental hosptial, and the other characters were the doctors trying to help him, or other patients, and all these puzzles were little tasks they'd given him to help him reconnect with the physical world and keep him occupied, so he wouldn't hurt himself or others. It kept the occasional non-intuituve answer from seeming pointless, and as time went by it got more and more fun to point out, you know, "More evidence for the asylum theory!"
They left off on the world of Knockoff Skyrim in the Clouds, and I kept going. And I kept finding more and more places where the asylum theory fit. The children left alone after their mother died. The nonsensical way the puzzles and worlds are connected. The way the Grain of Life connects to the Stardust. The fact that everyone who helps you can only help to a certain extent, even though they are supposedly the masters of their realm - one even says, "The rest you will need to do on your own." The way Umang is pushed over and over and over to journey to these lands, and the way he is eventually pushed to, quite literally, travel to an alternate reality. And it makes his reaction to that all the more poignant.
(The only wrench in this plan is the Generic Evil Guy (TM) who gloats over his sequel hook/plot device, but I'm ignoring that because it's literally the only thing that stops this interpretation from flying like a paper airplane straight into the back of the teacher's head. And I haven't played the second one, or the third one if that exists yet, so I dunno, maybe I can make something up.)
Let me put it this way. On its own, this is a more or less stupid game with a hysterically funny plotline at best and a clunky, boring one at worst. Whoever came up with the proper nouns in this game should be forced to redraw all the characters as though they actually come from the cultures in which their names originate - for instance, I don't know that many blond white guys from India, and yet Google tells me that is where the name Umang originates. The graphics are as advertised: from 2007. The music is on a loop that's not long enough, and the audio transitions and voice acting are about as smooth and skillfully executed as me getting up before noon on a Saturday. At one point, if you fail to do several things in the correct order, you are treated to a blacksmith wearing some kind of flexible metal (?) staring at you/Umang with what appears to be unrepentant (though restrained) lust (??), and you are allowed to repeat this five-second cutscene as often as you like (???). I turned all the sound off partway through and substituted in the Pacific Rim soundtrack, which by total chance played "Mako" at exactly the right moment to give the ending cutscene a beautiful, ethereal, almost transcendent
On the other hand. I love what I was able to make of this game. I love that I can share it with everyone else, and that the narrative was free enough that this is a viable interpretation. I love the puzzle solving and the fact that for the most part, there was a great balance between the amount of effort I exerted to solve the puzzles (at least, the ones I didn't peek on) and the cutscene, item, new area or plot detail I was rewarded with (this is definitely a game for people who like shiny things).
Overall - if you'd like the game to carry itself and take itself seriously, don't play this, because it's not what you're looking for. If you'd like to solve some puzzles and maybe laugh a little at the absurdity of what's going on, at least at face value, and then find meaning in your own interpretations - then this is perfect. I wish you good night, good luck, and a good imagination.
As for the accusations of this being a Myst knockoff... I've never played it, but thanks for the game recc!