I've been seeing recommendations for this game for years. Especially among the top Survival Horror titles of all time, it regularly makes the list. Eternal Darkness is also notable in that it was the first game Nintendo published with an 'M' ESRB rating. Other than that though, going in I knew only that there was some kind of wonky sanity mechanic, multiple paths for your playthrough, and an iconic main character who's yet to re-appear since. What I didn't expect is how frankly bizarre this game is overall. For one, it's barely a Survival Horror in many respects with fairly plentiful ammunition and a reliance on unlimited spells (!?) that can keep you going regardless of poor resource choices. Further, if I were to—somewhat poorly—try and give the one-liner description of the premise, I'd say it's kind of like Tomb Raider and Assassin's Creed meet Lovecraft, but it's a Survival Horror game with spells. While in some ways, I think the game tried to do a little too much and the consequent rough edges show for it, I ended up really enjoying my time with this weird-ass title. I expect most of this review will just be my attempt to explain all the peculiarities throughout it.
Perhaps the thing that surprised me most is that I have to disagree about Alex being an iconic protagonist considering you barely play as her throughout the game and the vast majority of the time you control one of a large cast of characters throughout thousands of years of history. In fact, of combat segments, Alex doesn't really have anything significant until the final chapter of this ~15 hour game. Generally, Alex's parts act as very brief interludes exploring her family mansion in Rhode Island which is (mostly) pretty safe as she discovers hidden magical pages that allow you to play another chapter in the long-running generational tale that tells the story's events, going back as far as the Roman Empire. Once you find one of these pages, you'll control a character exploring one of a handful of locations in the game with several characters visiting the same places, often centuries apart. This was shocking to me as I didn't even realize there were other playable characters, let alone that there's 13 and you play as characters other than the protagonist almost the entire game. Still, once I got used to it, this setup was actually super interesting and made for such an innovative way to tell a very long-running story taking place over 2 millennia. There's also a bit of fun immersive exploration of the different times and places that come with each perspective.
Another surprising thing to me was the spell system. I suppose I had no reason to think there wouldn't be straight-up abra-kadabra magic in this game, but it's just not something I'd foresee popping up in a game with this gameplay otherwise. The spell system itself I found hit or miss. You discover runes throughout the game that can be combined to form spells, limited by the different runes you've collected, the level of your spell power so far, and what combinations create viable spells, leading to about a dozen spells that can be cast at higher levels with different potency and warped by the different elder god attunements you have available (more on that in a moment). You also will find scrolls that just tell you what rune combinations can work, which saves some pain, but you can technically craft the spells whenever you have the right runes. Your magic pool (let's just call it "MP") replenishes as you walk around, so you are essentially unlimited in how many spells you can cast throughout the game. The spells also have varying effects and while this was a cool system at first glance, several of the spells—especially if you get the hidden fourth elder god attunement rune—feel vastly over-powered, especially given they can essentially heal and shield you infinitely if you have the breathing room to cast them. The rune combination mechanic is a little unwieldy as experimentation is a slow-going pain given the menus, but the actual casting of spells was also annoying with the way the spell is canceled and the MP still expended if you just accidentally bump the control stick at all while casting.
Now, about them elder gods. This is yet another odd feature of Eternal Darkness in that the first trip into history allows you to pick one of three colored symbols representing one of three elder gods, Ulyaoth (blue), Xel'lotath (green), and Chattur'gha (red). There's also a fourth elder god that is referenced throughout the story, Mantorok (purple), but they can't be chosen in this way. I went with Xel'lotath without really understanding the impact of the choice, but this will shape the entire game in some way. I don't totally understand all the effects, but as I understand it, even all the basic enemies will function a little differently based on the god you choose and some of the final bosses will at least have a different appearance. There are also multiple endings based on which one you choose, as well as a true ending if you beat them all (which sheesh, would take a long time, this game is pretty lengthy for a horror game). But further, you will obtain attunement runes for each of these gods that changes how the spells you cast function. For example, casting Recovery attuned to Red will heal your health and when attuned to Green will recover your sanity. Further, the gods oppose each other in a rock-paper-scissors format like Red>Green>Blue>Red (which yes, I remembered as Charmander, Bulbasaur, Squirtle). This means if there's a Green enchantment you need to dispel, you want to cast a Red Dispel Magic spell. The god you choose to oppose at the beginning shapes a lot of the kinds of spells and effects you need to deal with, so for instance a lot of my spells to solve puzzles were attuned to Red to dispel Xel'lotath's Green spells. It was all very weird and the game really could've explained some of this stuff better, but I found it really interesting once I got the hang of it.
Combat in the game in general was fairly basic and easy. There are a few exceptions, but the vast majority of the game, the fights are trivial with most characters having solid methods of dealing with the enemies they'll face. A couple bosses later in the game have very particular mechanics that were more difficult, but for the most part, the game is pretty easy with simple encounters solved by some button-mashing and basic timing. Even if you mess up, as long as you survive the fight, you can just heal up with magic.
Then there's the Sanity mechanic this game is so well-known for. You have a sanity bar, just like your health bar (but green!) that goes down when encountering the supernatural and other scary things. I believe I faced more of that due to opposing Xel'lotath. As your sanity decreases, the game's presentation will warp drastically, often in rather meta ways to make you think your game is broken. Some of these are subtle like the walls of the room will appear to bleed (an effect that probably would've been a lot creepier if the graphical effect weren't so shoddy-looking). But the game will also start to try and mess with you as a player, for instance showing a giant volume bar at the bottom of your screen deplete, making it look like you sat on the remote and turned the TV down (which might've been more effective if I'd seen a volume bar look anything like that since like 2005). Another fun fuck-you sanity effect is you walk into a room and suddenly there's like 6 zombies right by the door you came into and they start attacking you but your screen shows a "your gamecube controller has come unplugged" error message, making you think you're going to die because the game didn't pause while you had a disconnect. That is a good example though of how while these were all kind of amusing effects, the sanity mechanic doesn't really affect the game much since ones like that will just respawn you after it's done messing with you for a bit. Further, while I think they were super clever and amusing, I personally don't get the "horror" aspect of them as while sure it's scary to think you're about to lose progress because of a weird glitch, the controller disconnect for instance just takes me completely out of the game and makes me immediately think more about my hardware than any real in-game horrors. But alas, I admit it was a valiant troll.
The only other thing I'd comment much on is the general presentation of the game. I think it's mostly fine for its time. It's on the Gamecube and the game doesn't look fantastic, but the graphics are fine for their time. The music also evokes good atmosphere. The thing I don't really like is despite this being Nintendo's "edgiest" game yet, the art and animation all just feels a little too cartoony. Throughout the game, I never really felt like I was playing that much of a horror game because the zombies and other ghouls felt more like goofy-looking blobs with funny animations. Despite the general dark subject matter, some of the characters make the game look more like a licensed game of a Disney movie or something, which made it harder to take seriously.
All in all, this is a super weird game to me. Perhaps if I'd done more research ahead of time I would've expected as much, but it really caught me off-guard and that's one reason it took me a good year to pick back up after playing the first couple chapters. Frankly, if I were just judging it on how fun and engaging it is, the game would be a low 3 star as the jank is unfortunately pretty pervasive. However, there was just so much intriguing oddity throughout the game that fit well its cosmic horror that I found the game rather charming. It probably would've left an even greater impact on me if I'd played it when it came out 20 years ago, but Eternal Darkness still manages to be such an intriguing experience once you give it a chance.