Absolutely amazing game. It just looks so good, feels so polished, and the level design is amazing. I love the premise of the skeleton wanting to see the sun, it's so wholesome and vague, and the soul trying to guide the decomposed body is just so natural. The chain that holds them together is so real, every time you try to separate them the soul is pulled back, the screen shakes, that satisfying sound, you just feel it. The challenge comes from trying to open your mind to see the world differently, the soul helping you realize that your perception is flawed, much like in real life you could say. It's the kind of game that punishes you for not playing perfectly, not always being careful that there might be hidden dangers, and after many deaths you know the world perfectly and you feel amazing for passing through it flawlessly, due to your past failures. The levels are carefully crafted, and I love the fact that at some point the map loops back to the last checkpoint and opens up a new area, making the world not feel linear. This reminded me a lot of Bloodborne, just on a small scale.
Then you gain the ability to double jump, opening more areas once again. Just when you were starting to rely on your soul too much, everything is flipped with those seemingly Celeste-inspired blocks that only the body can pass through. You now have to carefully protect your soul with your body, while still making sure to reveal the path with the soul, just like in life your "soul" guides you, but with your body you can destroy your soul. Maybe I'm giving this game more meaning than it was intended, but I just love that it can be interpreted this way and it fits so well. As you go further towards the "real world" there are many more dangers for the soul, signaling that it doesn't belong in the physical world. The ending is cute, you finally get to the sun, but you could definitely include some sort of animation for a more satisfying conclusion. The same goes for the beginning, some awakening animation would definitely fit. The text does a good job, however.
The dark graphics with a little light here and there are so simple and so atmospheric. The sound design is amazing and it is just silent enough to make you feel lost, with that ominous soundtrack. One small complain here would be that the sound you make when you walk, though boney and atmospheric, just hurts my ears when I walk too long and hear it looping, there are too many ticks and it's kind of scratching my ear, I would like too see it made a bit softer, hope you can understand where I'm coming from. The jumping sound, however, is very satisfying as you don't have to hear it looping and you can just hear the bones. Loved the minimalist "3d" animations on the UI. I have to ask, is the game made pixel by pixel or did you use a shader or something like that to give the impression of pixel art? The ghost looks like it's the latter, while the skeleton looks like it's made pixel by pixel, that is why I am confused. Either way, it works really well. The cursor just doesn't need to be on screen, although maybe that's just because it's webgl. Definitely remove it if you can. The game does a great job at explaining mechanics without any text. I think the character controller is a tiny bit too sensitive, as this is not a fast paced game and sometimes you walk too far and that adds to the challenge, I don't know how intentional this is. It is so easy to lose when you touch the black blocks with your soul that it makes certain parts very frustrating. I feel like hard and frustrating are different things, it just feels a bit unfair when you don't think you touched it and you lose, especially towards the end. If this isn't your intention, I recommend making the ghost collider a bit smaller, to be more forgiving.
Overall fantastic game. If you accomplished this in a week, give yourself 3 months and make a full Steam release. You could surely make something great in that time. You could flesh out the story, add more mechanics and even improve the graphics, even though it looks great, more layers could be added. You definitely don't seem to have a problem with pacing or level design, so I feel like now that you have this game you can easily add a lot to it. I am definitely reading too much in the story, but I love the fact that it's ambiguous enough to let me do that. Fantastic game, probably my favorite from the jam. Good luck in the future!