With many forms of art, I tend to judge them by how much I wished I'd created them myself. The Talos Principle is already in that category.
It's extremely easy so far but I think the first few puzzles are designed almost as a tutorial to gradually introduce you to concepts in the game.
I love, though, that it doesn't feel like a tutorial. You turn up on this world with no information about what to do or how to play and it's gradually revealed as you start exploring.
I'm at the very early stages (only played for 20 minutes–as Martin says, it's very easy to play short sessions) but it's atmospherically gorgeous so far.
On the strength of Martin Brochhaus's comments in his stream of the same name, I bought The Talos Principle last night.