It's not particularly big brained. Just very enjoyable to have a game world you can discover on your own and with some intriguing mysteries. You have to explore nooks and crannies, some stuff can be a bit hidden, a lot of optional content and secrets. Not everything is immediately spelled out and instantly gratifying. A lot is conveyed through environmental storytelling, atmosphere, worldbuilding. There are a lot of puzzles you cannot immediately solve, but you just have to backtrack later once you find a hint or item elsewhere. A misconception is equating this sort of design with challenging, but it just means elegant and satisfying. It's not big brained, but it doesn't take you for an idiot.

It reminds me more of older RPGs with good exploration. Like STALKER, Witcher 1, Gothic, Morrowind. Or even point and clicks.