An absolute gem of a game and one of the most commited to implementing the theme. This is honestly impressing.
The start was a hard balancing act but I love how little handholding there is, despite how cryptic the game looks. Reading the spellbooks gives all the tools needed to understand how to approach each puzzles and encounter, it's absolutely lovely how you made such a complex system without needing a tutorial.
Movement feels great, the camera position and fov are expertly set up, this is one of the very best in this regards. I did feel that the game lacked some landmarks to make exploation easier, the minimap never showed for more than a few step and getting to the latter parts required quite a bit of memorizing (or drawing an actual paper map).
Nothing too major but I also though it would be better if our energies harmonized by themselves after every death, I kept forgetting to re-harmonize when respawning and ended up dying quite a few time when going back through the portals.
Fantastic entry overall, top notch on every aspect.