Outer Wilds: Echoes of the Eye Review (doing my best)
Short version: I think the DLC is worth playing, and I think it's best enjoyed after beating the main game. It plays a little different from the main game, but it's worth getting used to.
Extremely vague and broad Thematic Spoilers without context: I think it's an interesting shadow cast behind the main game's story and themes. If the main game is about fearlessness, this game is about fear. If the main game is about seeking, this one is about hiding. If the main game is about facing the end, the DLC is about turning away. It won't feel the same as the main game, but that's not an accident.
Longer version:
Like the main game, you theoretically can do everything you need to 'solve' the main story of the DLC the second you step into the location, if you only had the knowledge. Like the main game, you can get that knowledge by doggedly searching for lore and clues, or by just messing around, experimenting, and/or getting lucky.
There are some difficult to navigate portions; the game provides some shortcuts but I admit it can be a little repetitive to redo these routes despite that, especially if missing one stop can mean needing to go around the ride again.
I think it's best to play this after the main game, so you're free to jump right back into it after every cycle, and so it doesn't distract from the main game's mystery. I also found going into it after mastering navigating around the base game planets made physically travelling through the areas easier, and allowed for more confidence in trial-and-erroring knowing the base conceit of Outer Wilds' setup.
There are parts of this game that I suspect are annoyingly difficult on purpose to make the player desperate for an alternate way around the problem. And there are ways around those segments - even ones that aren't the game's 'intended workaround'. I recommend for anyone stuck on Those Portions of the game to start thinking about what exactly you're struggling with if it's actually necessary. Thematic spoiler again, but much of this game is about not taking the route you've been trained to expect.
This is a rare DLC which has an answer or two to unexplained things in the main game without dimming the magic of it. Perhaps the answer wasn't needed, but what this answer brings to the vibe is interesting in its own cosmic-chance kind of way.
All that aside: Between the base game and this, I didn't realize how much I needed 'rustic sci-fi' and 'rustic spaceships' until this game and DLC! Likewise with experiencing the kind of campfire horror, haunting forest, haunted house vibes in space. Extremely good aesthetics imo.