I know I shared a lot of thoughts already, but here's some attempt at organizing them on the page.
I like the quest overall, but it's some what of a mixed bag in some places. In a lot of ways, I feel like it's the kind of quest that is better in hindsight than in the midst of things.
The overworld is cool but definitely very cryptic. Has kind of a Zelda 1 feel to it even though it leans on entirely different mechanics for hiding secrets than Z1 does. I'm generally okay with it, but I wish it were slightly less cryptic in one or two spots. Not sure how to tone down the difficulty a little without making it too obvious though.
Dungeons were neat for the most part. Level 1 was kinda just there, but it works. Level 6 (what is game progression?) was simple but a blast with the mechanic. Level 2 was fun, though had one or two annoyances. Level 3 was perfect, no notes. I especially love how bringing in Level 4's item lets you explore it differently but also doesn't completely trivialize it. Level 4... man. I want to like this dungeon, but I ended up coming away very negative on it. I think most of that boils down to the jumping in sideview just feeling kinda awful. Probably fixable, but man does it bring down the experience.
Then special shoutouts to Level 5. 10/10 dungeon. My only real gripe was with that one switch in that one room, but even then it's skippable. I know most players seemed to bounce off it, but it was legitimately the high point of the entire quest for me.
I do wish the final boss had a second phase, but given the timeframe the quest was built in, I'm kind of amazed we got as much contest as we did. Lack of a second phase was literally the only thing that felt "incomplete", and even then, that's only because I know you well enough to know you wanted one.
The inventory was fun to play around with, even if a certain ability walks the line between awkward and busted. You made magic stream fun, and that alone is pretty impressive.
Story... man. I'm impressed you somehow revived all those ideas from 13 years ago and mostly made them work.
All in all, it was pretty fun. I have some gripes, but it was my favorite entry of the contest despite them.