izigame.me

Such a strange specimen. Released before the indiepocalypse and with exceptional production values, it was a guaranteed hit. And make no mistake, this is a game very much worth playing - but. There's always a but, isn't there.
This is not really a metroidvania, this is a precision platformer masquerading as one. To avoid arguing genre semantics, let me focus on what do you do most of the time. In metroidvanias, you usually spend time exploring, trying out different paths and fighting enemies - here, most of the time will be spent trying to perfectly execute the complicated maneuver required to progress to the next room, at least in the second half of the game. The first half for some reason plays like a more straightforward metroidvania, witch branching paths and whatnot.
In other words, this is less "Hollow Knight" and more "Celeste".
And to make things worse, the story and the general aesthetic feel a little mismatched with the gameplay. The story is a wonderful fairy tale which will pull your heartstrings, but the gameplay mostly causes you to feel anger-fueled determination (ARGH I ALMOST MADE IT. I'LL BEAT THIS !@#$ LEVEL, JUST SEE IF I DON'T). And since the game is very good at making you care about the characters and the world, you REALLY want to see it through to the end - it almost turns to desperation, even if it's not -that- difficult (I'd say it's easier than Celeste).
Here's a little more in-depth analysis, spoiler-free.

The Gameplay

At first, it's a pretty typical metroidvania. You jump, you explore, you uncover the map, you collect abilities and gain experience points to unlock perks. Occasionally you find a hidden nook which contains an experience boost or a health/mana container. Standard stuff.
What's unusual right from the start is the checkpoint system. You can create a "Soul Link" which serves as a checkpoint and a minor heal. It uses mana, which doesn't regenerate, you have to collect it from the environment. So managing your checkpoints is a mechanic, and as you upgrade Ori, it becomes more and more involved. This is a pretty good foreshadowing for what sort of difficulty the game will have later.
The combat is also unusual. You have an auto-aiming friend "Sein" who attacks multiple targets at once on a button press. In other words, you merely need to be in the general vicinity of the enemy in order to be able to damage them. There are certain enemies that require some trickery to defeat which keeps things fresh, but in general the combat feels more like an annoyance, an obstacle to what you really do which is platforming.
And, indeed, after the first act, the game's true form comes into focus - the precision platforming. Suddenly, there's lots of pits and spikes that are almost instakill. You're given an ever-expanding arsenal of abilities to deal with that: double jumps, dashes, wall jumps, all sorts of classics are here with interesting twists. And for what it's worth, the controls are fluid and precise. My only complaint was that when I wanted to do a ground pound I couldn't, but when I didn't, it happened. And yes, I died many times because of that, but that might've been due to the faults of my controller, or maybe I just messed up? Who knows.
Oh, and for the most part, whenever you get past an obstacle, you're allowed to create a Soul Link ("save"). However, there are three "boss fights" - challenging chains of difficult platforming sections which you always have to complete in one perfect go. There is no actual boss, you're usually running from something. That showcases well where the game's priorities and strengths really lie, as they're hard but wonderful.

The Fluff

Now let's look at the pleasant stuff. The music, the look, the story. All of them are very fairy tale-like. Music uses leitmotifs in an effective way; it's mostly leading flute with strings and piano in the background during more intense segments. The look... do I even need to say anything? It looks stunning; smooth, wonderful animations, detailed models, vibrant environments. Usage of colour is top notch. It's arguably the game's strongest point.
Wait, no, it's actually the story. If you're sensitive, it will probably break you. I know it did break me. I felt elation, I hoped, I cried, I despaired, I experienced relief, I cried again. It's a wonderful fairy tale which strikes deep into the very heart of makes us human, no, into something primal, that connects all living beings. If you think I'm blowing things out of proportion... just try it. Explaining would spoil things, so I'll leave it at that. No matter how dark the night, the dawn always arrives.

The Blind Forest

I haven't played the sequel as of writing this, so I can't comment on how it compares. I just know that the very existence of it spoils a few things. So be like the forest, just get this and go blind.
Just be warned that you'll need patience and skills. Treat this game like a precision platformer and you'll be fine. If you can't handle the difficulty, then this game is probably not for you, and that's fine - but there are difficulty settings, not sure if they'll help with the platforming, though. Hope that helps!