I've played a little over an hour, probably. I'm enjoying it.
The game has a very nice vibe. It's relaxing. The world is very pleasant to look at. You explore at your own pace. The audio is quiet, subtle, and understated. I'm a quiet, introverted person, so I appreciate that (vs. the bombastic soundtracks you get on other games). I haven't used headphones yet, but I'll bet they make it more immersive.
With the mentions of Dark Souls, I expected combat to kick my behind, but it hasn't. It's been very manageable. Of course, I'm early on, so that may change.
Some reviews made it sound very puzzle-focused, but I'm not finding it to be that way. To me, it feels more like an environmental exploration and route-finding game. There are some environmental puzzles, but most of the time, you are just finding your way through the environments, exploring, finding upgrades, seeing what areas those upgrades open, etc.
I'm confused about some things, like what the different objects do. There is no tutorial or even words to help you out. I'm sure I'll figure it out in time.
Anyhow, I'm enjoying it so far. Quality piece of work.