it is quite a rare thing in this industry nowadays for a game to be genuinely innovative, something that cannot be neatly placed in any one category or easily compared to other works. you could say that rain world takes cues from survival games and metroidvanias, but the crucial bit is that it doesn't let itself get constricted by any genre conventions. it borrows what works and leaves behind what doesn't. how easy would it have been to emphasize the combat a bit more, expand the offensive capabilities, add some bosses here and there? how easy would it have been to make the levels a little bit more neatly structured and paced, to gate exploration and progression behind a lock and key structure? how easy would it have been to make the enemies a tad more predictable, more exploitable, more "fair"? in all likelihood these were enticing temptations; they're tried and true methods of game design that would've served to make the game more marketable, more familiar, more accessible - and worse. instead, rain world has the courage to coalesce into something original. something new. something that's not afraid to question even the most entrenched pieces of game design wisdom, like the notion that games should always strive to be fair, or even fun. it's the sort of game that this industry desperately needs more of. in a just world, this will be looked at in about a decade or so as an influential classic that spawned many imitators and successors. there's no guarantee that'll happen though, because, as rain world itself takes care to remind you, the world doesn't operate on just principles. sometimes, all one can do is hope for the best.