The Turing Test
This first-person puzzle game is one of the better Portal clones out there. It has a good background story, interesting puzzles, and smooth gameplay. It's generally easier than Portal, which may be a good or a bad thing according to your preferences (and I.Q.).
It does have two flaws. First, as other people have mentioned, there's weak continuity between puzzles. You might learn a new and clever trick to solve one puzzle, but few of these tricks are put to much use in subsequent puzzles. It feels like a missed opportunity to create a deeper sense of progress.
Second, it's uncomfortably similar to Portal. The visual style is almost identical. The rationale of the puzzles is also almost identical in both games (they are tests). The story, though original and terrific, touches on similar themes to those of Portal. And even the actual gameplay mechanics are very similar: we get cubes, panels, buttons, lasers, bridges, etc. All that's missing is a portal gun. Is The Turing Test a homage or a ripoff? Probably a little bit of both.
Surprisingly, the developers' previous and much shorter first-person puzzle game, Pneuma: Breath of Life, is a bit more original, though it, too, "borrows" a lot from The Talos Principle. Is it really so hard to come up with original ideas in this genre?
Nevertheless, this is a very good game, if not a great one. It nicely scratched my Portal itch.
Note that the DirectX 12 version doesn't work well for many of us. It didn't work at all for me.