Early 2017 was a pretty good period for Metroidvania games. In February we saw Hollow Knight land on PC, and just one month later, a scrappier, weirder game called Rain World hit PC and the PS4. Hollow Knight, of course, now has the spotlight - it's one of the most successful and beloved indie games of the past decade - but Rain World also made a splash (pun not intended), just in a much more subtle way.

Rain World's one of those where even long before its release, you'd see GIFs of it across social media. Thanks to gorgeous and peculiar traversal mechanics (slinking up walls, sliding through pipes) and a wet, collapsing world brought to life with jagged, fluid pixel art, Rain World really lends itself to short, sharp clips. Watching your character, called a 'slugcat', slink and slide through pipes and peel itself off walls and cram itself into little nests captivated me before launch, and said GIFs did their job - I couldn't wait to get my hands on it when it finally released.

I've always been surprised it didn't capture the public's imagination as much as Hollow Knight. It too focuses on exploration, survival, and implicit storytelling, and even boasts a similar doomed, lonely world as set dressing, to boot. The combat isn't as satisfying as Team Cherry's insectoid platformer, granted, but the desperation communicated - through your slugcat's use of debris and spears to defend itself from the threats that prowl around the obtuse, post-industrial ecosystem of the world - certainly works. The twist is, here, you want to avoid combat, where possible: there's a distinct sense of predator versus prey in this game, and you are not at the top of the food chain.

The rhythm is hard-going and slow. Finding spots to hibernate in is tough, and it makes each of these cosy nests feel even more vital and valuable when you finally manage to tease one out of the meandering, labyrinthine world design. You also need a decent stockpile of food in order to hibernate (and, henceforth, save your game). Honestly, watching slugcat finally curl up in a nest, rest, and replenish its stocks of energy feels even more satisfying than finding a bonfire in Dark Souls. Really.

Once you manage to make sense of the map (it'll take you a while), you'll find that even progression is gated by a rudimentary health/life system: you need 'karma' in order to progress from one area to the next, and 'karma' is - here's that Dark Souls reference again - lost upon death. You can recover it by hibernating, or eating certain flowers, but you need a certain amount of 'karma' to get into gated areas. The result? Terrifying, deathless runs from one area to another. You need to memorise threats, know your controls, and be responsive: a lot of Rain World's animations are procedural, so simply relying on muscle memory for your desperate flights from one area to another is rarely enough. For a specific kind of platforming sicko, though, it's (slug)catnip.

Enemies are not just constrained to the screens they spawn in, either. Each of the predators wanders independently of you, and cares little about your struggles in this world. At one point you'll no doubt slink into an area and find two lizards battling it out, all teeth and fangs, squabbling over territory. The first time I played it, for instance, there was an enemy that completely stumped me, blocking a karma gate and therefore my progress. On my last, exasperated attempt at figuring out what to do, I entered the screen and it was dead, assumedly killed by something bigger and scarier. That's it, I thought at the time, the game is an all-timer.

Rain World also takes a mystifying, three-tier approach to storytelling. For the most part, you can piece together what happened to this watery hellhole via the environment, eking out little glimpses of a world that was, in amongst all the urban decay that lingers here now. Slugcat will also dream when hibernating, giving you a snifter of backstory whenever you actually manage to rest. There are also holograms dotted throughout the map, giving less obtuse hints about the events that lead to the current day. Your only guide is a weird little worm that will generally guide you towards bigger story beats. If you like waypoints, handholding, or clear direction, this game is not for you.

The result is a game that really emulates the feeling of survival. A game you play as an underdog. Yes, you can hunt and kill and eat and survive. But you are also, perpetually, being hunted. It reminds more of the Oddworld games than any direct genre stablemate - both in difficulty and tone. In Hollow Knight you're a god-like being, capable of hunting and eliminating anything that stands in your way. In Rain World, you are soft, tasty and vulnerable, and will often find more success in flight than in fight. It remaps your brain (at least, it does if you grew up on a steady diet of Metroid and Castlevania) and represents one of the lesser-explored peaks of the modern Metroidvania renaissance - and I think it's just as essential an experience as Hollow Knight.

It also, probably, would have enjoyed more success had it not launched against its nigh-perfect rival, and the fact it's now available on Game Pass will hopefully rectify that miscarriage of cultural justice, at least to some degree. It's only 3.5GB, anyway. Give it a download, and put at least an hour into it. Sometimes it feels good to know that no matter what life throws at you, you're capable of surviving.