Some thoughts after a few more hours of play.
I'm struggling with world navigation. I'm starting to understand the (overly abstract) world map, but I often can't figure out how to get from point A to point B, spending a lot of time going in loops trying to get out of a hub area to a new location. For instance, I know there's this really important room early on with all the doors requiring different numbers of cubes to open. But I have no idea where it is or how to get to it, now that I have a half dozen cubes found.
I'm starting to see all the things I can't quite figure out, but I'm not sure how to figure them out. Lots of totems the cube tells me it can't remember what they're for; puzzles involving stacks of movable blocks I don't understand; something involving some language/writing (I think?) that I can't decipher; I have four or five treasure maps and I have no clue what any of them mean.
At this point, my big question for the game is whether they're going to teach me what these things are, or whether they're one of those things I have to guess or find out online. It's been some time since the game actually taught me a new mechanic; there was an initial rush of learning the game mechanics, and now there's just cryptic stuff everywhere.
Game performance is definitely detracting from the experience. I just got a big new area, where they do the long rotating pan through the world, and it was at a low framerate and chugging the whole time. Really took away from the excitement of finding a new area. The game really needed more time to polish that stuff up.