Well, I spent 20 hours in the game and here's what I can say

1. Art style.
The game looks absolutely amazing. The world is huge and diverse. There are many different looking locations here that have a narrative design. Sometimes you can just stare at the backgrounds.

2. Metroidvania.
The world is huge and full of secret places. You can wander for a long time, and it is really interesting to explore. World is really interconnected.
Though it's annoying that sometimes the passages are blocked by enemies. At the same time, enemies respawn every time you enter a room. This slows down backtracking a lot.
And there are also many places that require some ability to get to. But once you get there, you'll find that there's a passage that requires another ability. And you've already walked half the map to come here and ask yourself "why the heck did I come here?"

3. Regular enemies
Dull. Usually they just walk back and forth, or simply throw projectiles while standing still.
There are very few enemies with more than one action.

4. Bosses
Not bad. But not very good either. Most of them could be beated by 3-5 attempts.
Many are preceded by unskippable cutscenes that are just annoying. Couldn't beat the boss on the first try? Watch the cutscene. Couldn't on the second? Again. You are punished by watching this annoying cutscene. Again and again.
In addition, bosses often have a completely non-obvious collider, and it is impossible to understand which part of the boss deals damage, which can be hit, and which is just for visuals.
Some bosses have very short and non-obvious attack openings.
Also, bosses like to fill the entire screen with flashes, particles and huge glowing projectiles, so that you stop seeing the boss, your character, and anything else.

5. Items
Active items are variations of projectiles and AoE.
Passive items more interesting and similar to Hollow Knight charms.
And also healing items. Maybe it's my fault, but I spent the first 15 hours with only one of them. Only after that I collected three more at once.

6. Currency
There are two types of currencies and a bunch of consumables in the game. And this is a problem. Every time you find a new secret, you hope to find something interesting, but there lies another useless artifact fragment or a bunch of currency.
Seriously, by the 20th hour I already had 20,000 currency and about 30 artifact fragments, and that's not counting a whole bunch of other junk.

7. Fast travel
The WORST part of the game.
Firstly, fast travel requires unlocking a skill that is hidden behind an optional boss. That is, you can just walk past. Because this is a metroidvania, you can go through it in different ways. And the first 3-4 hours of the game can pass without fast travel, and you will have to walk. And the world is HUGE.
Secondly, there are not so many fasttravel points, and they are quite far from all key points and NPCs. And the world is huge. Be prepared to walk A LOT.
And the cherry on the cake - fasttravel comes with an unskippable cutscene! Every time you need to go somewhere - watch the cutscene. Went the wrong way? Watch the cutscene! Over and over and over and over.
I think out of the 20 hours I spent in the game, at least 2 hours were just watching this annoying cutscene.

8. NPC
The characters are quite colorful. It is interesting to learn their stories. The problem is that the stories usually seem underdeveloped, and the characters themselves give a lot of uninformative dialogues that are simply boring to read.

9. Side quests
Usually, "bring me that", "bring me 6 pieces of that", and I'll give you a useless artifact fragment or currency, which you already have a lot of.

10. Map
The map is not very useful. The usual for games of this genre map of multi-colored squares, on which landmarks are not displayed in any way. It is annoying that shortcuts are not always displayed. For example, elevators are indicated by lines, but their horizontal counterpart (the void) is not indicated in any way. The player must remember that this door does not lead to an unexplored room, but is a shortcut. And the world is huge :)

11. Hub location
The hub location at the beginning of the game is a completely useless and boring place. And if I hadn't accidentally entered it while passing by, I would never have known that after a certain point there is a huge amount of activity there.
Seriously, there is even a fasttravel point there! But IT NEEDS TO BE UNLOCKED FOR MONEY! Why?
Why is there no direct road to such an important place?
Why couldn't just make the fast travel point accessible from the start? Especially since the fast travel system is still unavailable until you get the ability?
For what purpose?

12. Resume
You may have noticed how often I write the word "Annoying" in this review, and this is how the game feels.
The game isn't bad, it's exactly annoying.
I don't want to watch that cutscene again, I don't want to read that block of text again, I don't want to kill that monster blocking the way again, I don't want to trudge across the entire map to check the passage again.
I just want to explore this huge, beautiful world.

The game had a huge potential due to an interesting setting and absolutely awesome art style.
But a lot of poor gamedesign decisions spoils everything very much.

If you like eldritch games or you like this art style and characters - you can probably play it.
The world is fascinating to explore, but the content of the world is not very pleasing.

A very solid Metroidvania. I appreciate the art style, the world and enemies are very atmospheric and the music is really really well done. My wife has stopped what she was doing to comment about the music in the game. Eternal Engine is a song that stood out to me.

Works flawlessly on the Steam deck.

A great dark soulslike metroidvenia.
I love it!