So, I beat it already, with 100% completion on the main game. There's a harder hero mode afterwards that I haven't tried yet, maybe I'll do that when travelling instead.
I enjoyed it, but I think the familiarity with the map hurt it a lot. Part of the wonder of the game is supposed to be exploring a new world, but it didn't feel very new considering we'd seen the world before. I mean, the second 'world' had some interesting takes on things, but it still was largely similar to the dark world in LTTP. I know that was intentional, and also playing to nostalgia, but I do wonder if it was really a smart choice or not.
Also, it was a little too easy. I don't mean just battle difficulty though. I mean, other than a few enemies who take off massive amounts of health with one hit until you eventually upgrade your outfit, battles and bosses were easy. But worse than that, there weren't really enough hidden secrets. Heart containers were a breeze to find all of them. The Maimai things to upgrade everything, those were all simple too. Upgrading the sword the last time was nothing like the complication that it was in LTTP or the difficult path to the Biggoron Sword in OoT.
The worst part, difficulty wise, had to do with the non-linear progression. No, not just the item shop thing I already mentioned. But I mean the dungeons themselves. They designed it specifically to be possible to do any dungeon in any order and to give you the ability to have all the items right away if you really want. That's great, but because of that non-linear design it also means that as long as you have the single item that a dungeon needs, you're fine. There wasn't a single instance in the game where there was any clever combination of multiple items in some new way to solve a puzzle. In Link's Awakening, for example, sometimes you just needed the feather to jump, but other areas were only accessible with the boots and the feather. Or, for a more recent (and non-Nintendo) example, "Ittle Dew" on the PC was really great at this. Despite only having three items, the combination of uses and tricks there were to using those three items were kind of amazing (though admittedly it was a very short game not nearly on the same scale as this).
Overall, the puzzles themselves were mostly just simple stuff that we've seen a million times before in the Zelda series.
Now, all of this was negative here, but it's not as bad as it sounds. It's still a really good game. They nailed the feel of it, the plot was decent enough for a Zelda game, and overall I liked it a lot. It's just that it could have been even better.
In other words, LTTP and Link's Awakening still top this one by far, in my opinion. Still, that's some lofty competition to be up against and it at least is in the same (great) ballpark as all the other 2D Zelda games.