I haven't even come close to beating this game yet and I'm already in love with it. The controls are a dream and I love the direct Metroid inspiration. Fantastic game so far. I may or may not change my mind once I beat it, but at this point I'm inclined to stick with my current evaluation.
Does it have hard bosses? Yes. I had to read some forum posts to figure out how to modify my load-out/strategy to win. That includes "cheesing," which isn't ideal.
Some lore/story/exploration beats required obtuse solutions that I had to put in some research to find the solutions to. But it reminds me of OG Castlevania: Symphony of the Night. Things are hidden that reward either 1) meticulous exploration and experimentation or 2) having external knowledge of.
However - it's very few games I feel like sticking around ot 100% after winning. This game is fun to explore, fun to learn about the lore, which is mysterious, but not too much so to actually enjoy.
The voiceacting is superb. The writing is awesome. The only bug I encountered is the map system changing my custom-pins when I would close and restart the game. Again: less than ideal, but not game-breaking.
This game is worth playing. The main character starts with a simple premise, but by the end, after really exploring every nook and cranny of the map, her motivations evolve and become more sincerely and beautiful.