As you’ve worked your way through Returnal’s procedurally generated exoplanetary hellscape, maybe you’ve come across a chamber that looks a bit like this:
Yes, that’s lava, and no, you don’t want to step in it. Given the vague Metroidvania nature of Returnal—where it’s sometimes clear you can’t proceed past certain obstacles without certain upgrades—you may quickly deduce that you’ll be able to walk on it at some point, but currently lack the appropriate gear.
That assumption is absolutely correct: To walk on lava, you first need to unlock the Promethean Insulators—by my count, the only core traversal upgrade you can stroll right by if you’re not careful. Here’s how to find it.
Spoilers follow for Returnal.
You can’t nab the Promethean Insulators until you reach Returnal’s fifth biome, the Fractured Wastes. You’ll also need to have an Atropian key on-hand, so be sure to scour the prior region, the Echoing Ruins, until you find one. I’ve always managed to find a key on my runs through that biome, but I’ve sometimes had to venture down one of the two optional side paths that branch out from the chamber two before the boss fight.
Once you make it to the Fractured Wastes, you’ll quickly come across an antechamber with four branching paths. Three are mandatory; one is optional. Use an Atropian key to open up the optional one (identifiable as the dark blue triangular icon on your map). You’ll pop into a room full of lava with three platforms jutting out. Carefully jump across them, then use your grappling hook to zip across the rest of the way.
You’ll find a pedestal on the far side holding the Promethean Insulators, which, once equipped, give you “immunity against extreme elements”—or what you and I may describe as “you can walk on lava.” The Promethean Insulators are one of six permanent upgrades in Returnal, so once you get them, you needn’t worry about going through these steps again.
During my first few runs through the Fractured Wastes, I completely missed this upgrade. When I first reached the area, I laser-focused on the main pathways and eschewed all secondary routes, mostly using those early runs as throwaways to get the lay of the land. And then, one lucky go at it, I went the distance, unlocked the following region (Abyssal Scar), and never looked back. But I looped back through the Fractured Wastes on a recent run, and stumbled upon an upgrade (those lava-proof shoes) I’d written off as something I’d have to wait a while to find.
Personally—and I don’t mean this with a hint of snark—I think it’s supremely cool that I could stroll right past what by most measures would be considered a core upgrade. It’s refreshing that, after dozens of hours with Returnal, I can still come across something wholly new, even if missing it in the first place was a shortcoming of my own lapsed curiosity.
(Updated 3/3/22 with new details)