Rain World Review (Icebrick)
I'm not going to argue the game is bad. Enough people love it that I'm sure it's just not for me - but I do think you might want to think carefully before you buy the game and sink hours into it.
Now, I'm no stranger to difficult, esoteric games. I love Dark Souls, Outer Wilds, and Hollow Knight, but this game is by far the most frustrating I have played. I kept thinking I would "get it" or things would suddenly change, but I played an extremely unnecessary amount of hours and it never did.
The main gameplay is awkward platforming and avoiding/fighting various hostile critters. Along the way, you'll need to collect enough food to rest at a save point within a certain time limit. That's about it. Eventually, there is some joy to be found in flying through levels that previously gave you so much trouble with your skills and knowledge, but even that is often stamped down by frustrating mechanics. I enjoy big challenges where you can quickly try something again and again - RW seems to prefer the opposite form: mild challenge that sends you back 20 minutes if you fail.
As an example of one of these frustrating mechanics: when you successfully save your "karma" increases, and when you die, it decreases. Karma is required to progress to certain levels. In terms of actual gameplay, this mechanic seemingly only serves to make the game feel more frustrating. It's not even actually that punishing - at first you'll be scared and frustrated because every death makes you lost progress, but what happens in practice is that the first time you play the game you'll need to farm food for 10-20 minutes at the last save point in every area before continuing. Before you understand the game it makes it look worse than it is and discourages you from experimenting (when you definitely should be experimenting!), and when you actually do understand the game it just wastes your time.
I was unimpressed by the story. I will compare it to Dark Souls, since that is another series with an extremely obfuscated and unclear story. Getting a grasp of the story while playing Dark Souls is difficult, but not impossible and you'll likely at least get general vibes. If you want more lore, closely reading item descriptions is where you'll get the bulk of the content. In Rain World - I still don't know what's going on. Just playing normally you'll get very little of the story. There is a way to get more information, but it's not told you to you (I only learned of it after my third campaign when I looked it up online) and it's extremely tedious to use. Imagine if in Dark Souls you had to backtrack all the way to your starting cell every time you wanted to read an item description. And you could only carry 1-2 items at a time. And you could only teleport 5 times per save file.
I'm sure the game has some rich history and lore, but it seems the best way to experience it would be to look it up online - and I only wanted to do that once I beat the game. And I still haven't done that, despite the number of hours, due to the number of campaigns.
So... if none of that turned you away maybe you'll want to check out the game. It is fairly pretty and atmospheric, even if sometimes that makes it unclear what is and isn't ground, and the music is good. And as a tip, check out the options in the "Remix" menu. I ignored it the first time I played since that sounds like something you'd only want to check out after you've already beaten the game, but it actually contains a ton of helpful options that improve the game and which you'll probably want to enable.