Hypothesis: Outer Wilds is a masterpiece.

Unfortunately, testing this hypothesis is almost impossible without spoilers. This is a game you can only really experience once, and giving any details or specific examples inherently takes away from said experience, since it's a game so purely about discovery and understanding of the game's universe. Hence why so many people wish they could forget everything about it and play it again; why so many rave about the game, yet stubbornly refuse to elaborate.

So without getting into specifics yet, here's my spoiler-free recommendation:
If you love exploration games, cool sci-fi concepts, Groundhog Day-type setups, or if knowledge-based progression appeals to you, you owe it to yourself to play this knowing as little as possible. For some super high-level stuff, the visual aesthetics and soundtrack are both very nice and compliment the experience well, and I really loved the story, how it was told, and its synergy with a phenomenal gameplay loop. Approach the game with curiosity, and give it an hour or two to see what it's all about.

-----SPOILERS FROM THIS POINT FORWARD!-----

For all its intricate brilliances, I think something central to what makes Outer Wilds so incredible is surprisingly straightforward: it has one of the coolest, most imaginative and fascinating video game worlds I’ve ever seen! Like, just absolutely full of the most awesome ideas for planets/locations, incorporations of science, the life forms and their distinct cultures, customs, technology, ways of communicating, the central mysteries and their answers and implications, just... all of it! So many discoveries, inferences and connections had me like “gasp Oh my god! So [hastily thinking through implications]? That’s so freaking COOL!” Even after finishing, and then watching some streamers play it, it just gets cooler the more details I pick up on!

So much of the game’s brilliance stems from this. You get some unforgettable sights and spectacles from the worlds and finding out how they work. You get ridiculously neat mechanics built around quantum observation and entanglement, or navigating multi-branched Russian nesting doll Tardis space, or traversing the underside of a collapsing hollow planet crust with a wormhole in the center. You get some super cool puzzles, discoveries and set pieces built around these worlds/rules, your knowledge of them, and the time loop setup. You get this amazing feeling of awe and intrigue from learning some awesome nugget about the in-universe rules or what the Nomai were up to, suddenly realizing what to do with that information, doing so and then finding something even cooler! It’s a constant high of wander and wonder; no game has made me so excited just to explore and discover things before! I loved every minute of it.

All of this could have been squandered, though, if not for another piece of design brilliance: the progression structure. Having progress be tied almost exclusively to your knowledge of the game’s universe, rather than typical level progression, locked doors, new abilities and so forth is already a neat concept. But the true genius I think is in the inverted-tree structure both of access to new places, and of the mysteries/narrative itself. By this I mean that you start the game at the leaves, with dozens of eye-catching places to go that pretty much all lead you to a new bit of critical knowledge or narrative context - you can go anywhere and it’s basically guaranteed you’ll find something relevant, whether lore, rules, past events, present events, clues, or even just being able to observe places like “OK so we’ve established that space is all screwy here and there are scary lightbulb fish and I have no idea where I’m going; got it!” No place is wasted or unimportant. Every leaf matters. So right from the start, there’s so much that intrigues you and drives you to keep exploring and learning, no matter which of countless possible orders each player might discover things in. It’s true free-roaming exploration, perfectly balanced with guaranteed visual and conceptual hooks, and most likely progression of some kind.

Then branches start converging with others, you see connections and new breadcrumbs, and get even more invested in pursuing those, or returning to foggy death fish land with new biological expertise you discovered 5 hours later. But as you do so, you also keep running into new leaves, since they’re all scattered between the planets (instead of, say, one planet having all the clues and answers to one mystery and little else, potentially isolating the player to one branch of what’s going on for extended periods and creating a less dynamic or interesting experience). It makes it feel like there’s always tons to explore and learn and do and try, and also makes total progress walls or bottlenecks unlikely until right near the end, where things are converging to the final answers to each major mystery and there are only a few pieces left to play with. By this point, you have a clear idea where to look, and are, hopefully, less likely to get totally lost for hours leading to excess frustration or boredom. It's inevitably still a possibility, though, due to the game's hands-off nature.

And finally, the last piece of each major mystery converges to the true ending. WOW, what an ending! Heartbreaking yet hopeful, with some fun symbolic callbacks and crazy implications. One of the absolute coolest ideas in a game full of them. It’s going to stay with me forever. For such a high-concept world, I was so happy to see the game actually give interesting and satisfying answers to every mystery, and then stick the landing!

And that’s not even getting into the cool time loop stuff and how it both sets a gameplay precedent, and also ties into the ideas of self-preservation and inevitability present in the story. That's on top of just having some pretty cool puzzles and moments of tension built around how things change over the course of the loop (the Brittle Hollow quantum tower and how changing sand levels played into Hourglass Twins exploration being particular highlights for me). It also creates an ever-present sense of urgency during exploration, since you want to try and find everything in an area before the sun explodes! Fortunately, should you get caught with an unfinished area, the game makes a good effort to reduce potential tedium from backtracking. The scale of planets and distances between them is just right, and the ability to doze off to fast forward the loop, or meditate to reset it, are handy and welcome additions to discover. If you know what you're doing and pay attention to potential shortcuts, even the more hidden areas are maybe a 2 minute expedition, while most are more like 45 seconds. Just long enough to reflect on what you've found, what you've missed, what you'll do when you get back to your destination, etcetera. The Vessel is a rare exception, but for good reason.

I still feel like I've just explored the surface here. There's also the general vibes of everything, effortlessly traversing the full range from relaxing to tense to awe-inspiring to somber and back on command. Or the fact that you get a JETPACK through all this! It takes some practice and skill but after getting the hang of that thing, zipping around planets with it is so much fun! Or the clear sense of collective character and charm to each species, from actions and desires, to architecture, to writing systems and style of speech. Or the constant attention to detail that makes it feel like so much love was poured into this game.

Or how about the quantum freaking MOON with Schrodinger’s Nomai waiting on it, or all the crazy wormhole/meeting yourself/spacetime rift stuff, or the interloper ghost matter reveal, or the tense triple death fish drift in the final loop without the safety of the reset, with the invisible clock ticking, or so many other moments of greatness throughout!

...Ok, I’ve calmed down now, I think. Hypothesis confirmed!