simian.interface, by Vested Interest, is a game that never tells you the controls or how to play or what your goals are, but you'll immediately intuit all of those things just by interacting with it. In this sense, it's very toy-like: you're just playing with this thing, tossing it and turning it over in your hands. No instructions, hardly any rules.
Nominally, it's also a "puzzle game", but it really doesn't fit into the popular sense of a puzzle game. There's this concept of "filler puzzles" among puzzle games, where puzzles that don't demand any new skill or understanding from the player are not as valuable as more novel puzzles. You can be assured that in a Stephen Lavelle puzzle game, for example, every single puzzle has been consciously constructed and filtered and curated over the course of dozens of playtests. Same thing in Jelly No Puzzle: there's always a bit of additional new lateral thinking that trips you up.
In this sense, simian.interface is an awful puzzle game because it is made almost entirely of filler puzzles -- you're just doing the same thing over and over, and the shapes change a little bit. Most levels take about 15 seconds to complete.
... Except it's a puzzle game where the formal novelty of the puzzles doesn't matter?
That's because simian.interface is a puzzle game that isn't really about this sense of analytical "understanding" -- it's more interested in perception and brief but powerful moments, which I guess is a very different kind of understanding -- a tactile unspoken understanding of "feel."
The philosopher Martin Heidegger distinguished between two different attitudes of "being" along those lines: there's vorhandenheit ("present at hand") which is like a distanced analytical orientation to something, like you're studying it as a disinterested researcher -- and then there's zuhandenheit ("ready to hand"), which is like when you get "in the zone" when you're doing something, and that feeling / phenomenon defies description, and you don't really even notice what's happening. Heidegger talks through these concepts by imagining a hammer: sure, you could say the hammer's made of metal and wood and so on, but that's not really what a hammer "means" in the same way that it feels in your hand, or the way that a master carpenter might strike a nail perfectly without thinking. In this way, we usually regard zuhandenheit as truer, as more authentic, the attitude of being that wise masters have toward their craft: they don't think about it, they just "are."
Which isn't to say that players don't develop zuhandenheit when playing English Country Tune or Jelly No Puzzle -- I'm sure some players do, and both games are very toy-like. However, I'd argue that these puzzles games' awareness and avoidance of "filler" betrays their difference from simian.interface, and their differing attitudes toward being.
simian.interface argues that "being" is not something to think about, but rather something to feel about.