There's probably a lot I could but don't necessarily NEED to comment on here. It's good stuff to see in any case. I will say that a lot of spells, especially the ones that were created earlier, had their cost set somewhat arbitrarily and within a context where getting specific spells/more maximum mana was considerably harder. Due to the mechanics around them changing over time, spells could probably use a look balance-wise.
Also for what it's worth, I DO still want to write more 303, I just keep struggling with time management and putting it off when this game is taking up my focus. I definitely have things that I set up and still want to get to in 303, even if I don't actually completely finish the story (which is kind of a tall order considering how much detail I've already put into only the first week).