I just want to say that I was thoroughly impressed by the vision you sought to achieve, and equally impressed with the presentation. Your 5 years of research were not wasted!
The way the game flowed downwards complements the mechanics quite well, allowing you to backtrack if you forgot an important detail, and providing a moment of suspense as you wait to see what is materializing.
This begs for the addition of more components than just text, choices, and the dice. "Minigames", as I believe you phrased it. Think something somewhere between Undertale and what you have now.
The writing was strong, varied, fun and descriptive without being too prosy. My only complaint in that respect was that the early dialogue for your character is a bit terse and constrained, but it seemed to get better late game.
Combat was good, with interesting choices. There was a moment of intense satisfaction from the realization that I indeed felt that sense of agency you were aiming for.
The UX itself was inspired. Very clean look. Good bit of polishing in the cracks and crevices, and it shows. From the help icons next to the choices, to the detailed and generous colored artwork, to the health display, to the way you slowly introduce features in a way that seems natural to the story and not forced.
And the dice. Oh, the dice. Probably the coolest thing I've seen in a while. You actually found a way to make a rudimentary random number generator look visually appealing, and created a sense of tension that ebbs and flows. This is extremely hard to pull off in the digital format, because with physical dice you have this connection to the universe.
Whether you roll high or low, you feel a sense of fairness as the universe does not play favorites. You can see and feel all of the factors that determine the outcome, like wind, air pressure, the texture and weight of the die and surface. You also feel like you can influence the outcome to a degree by adjusting things like how you roll, how high you drop, blowing on / kissing your hand, etc. With digital dice, it usually feels hollow and fake, as you know the only thing determining whether you win is a single line of code. You don't feel any agency.
The idea of having more or less hearts depending on the likelihood of success sets the initial level of tension. This wanes to make room for the excitement of chance, of expectation of reward.
As the hearts begin to slow and lock into place one by one, and never the same boring way, the tension rapidly increases to its peak before even more rapidly falling flat and dissolving into either excitement or disappointment. This entire experience is modulated by the lightly colored text below the prompt that hints at how likely you are to succeed. Highly probable? The disappointment stings that much worse. Not likely? The satisfaction from nailing that strike is peerless.
This is probably my favorite mechanic of the entire game as it provides the backbone for an experience designed around manipulating your thoughts and emotions. Like slot machines at a casino, the moment of anticipation is greater than the reward, and affects your behavior and aversion to risk, leading you to sometimes feel that it is best to stick to the shadows and stay quiet, and other times playing you for the fool by causing you to get too bold in your actions before putting you back in line with a terrible roll. It would serve the experience well to focus on maximizing the dynamics it introduces to the world.
I could keep going, but I'll stop. Great game, I subscribed to the mailing list and eagerly await the sequel. If the scope of the sequel is large enough, it will set the bar quite high and pave the way for others to innovate.
If you could use a few hours of help a week with programming, design, or development of new mechanics, I would love to help you pioneer this interesting new twist on an old genre.