HIGHEST RECOMMENDATION!
"The Talos Principle" is one of the most enjoyable and rewarding gaming experiences I've EVER had and I've been playing video games since the Atari 2600 days. There is a reason why "The Talos Principle" is a hit among critics and the player reviews are "Overwhelmingly Positve." For me this is a new classic. A game that catches lightning in a bottle. One of those games that scratches an itch I didn't even know I had.
NOTE: If you think you might get this game, I'd recommend against watching video and looking at player screenshots. They are both highly likely to contain spoilers and inadvertent puzzle hints, both minor and major. I only played the demo going into the full game and I feel the experience was better for it.
This is a first person, sci-fi themed puzzler in which the player, an artificial intelligence, is left to complete puzzles by using a series of tools that are introduced throughout the game. The first tool is the Jammer, a tool that jams electronic devices and force fields. Another tool connects to and aims laser beams. You'll also learn that tools can be used in combination, keeping the progression interesting. Solving a puzzle rewards the player with a sigil (tetromino) which are then used as puzzle pieces to unlock new areas when arranged correctly in puzzle mini-games.
The only conversational contact the player has is with another AI program that often presents itself at computer terminals as the game progresses. The player is also, through communicating at the terminals and reading information displayed on them, left to ponder the role of the disembodied voice known as "Elohim", as well as the meaning of life, consciousness, being human, being alive, free will, and the afterlife.
The game itself is solid. Easy and tight controls. Very nice music, sound effects, and voicework. Clean, often beautiful graphics. Intelligent writing. No profanity or violence. Menus with many options like FOV, character speeds, FPS display, time display (something I never used as I chose to take my time), etc. Basically, I found the setting menus to be thorough.
Many have compared this to the Portal games, which is high praise. While both offer clever puzzles and a high quality experience, "The Talos Principle" only rarely depends on any sort of physical dexterity or reflexes. With those few puzzles that do require quickly timed movement, even the most casual of players shouldn't have any issues whatsoever.
While the presentation and story are high quality, it's really about the puzzles. What makes them so satisfying? First, puzzles do not need to be finished in an exact order. Leave one alone for a while that you are having trouble with and try again later. I found it interesting how I'd find myself struggling with a puzzle but after a day or two, the solution would become clear. It was almost "scary" when realizing how hard at work my subconscious was. I would also think about certain puzzles when not playing and come up with new things to try out. I found myself overthinking many times when the solution was much simpler. Also, just when I thought I had a handle on a "recipe" that certain types of puzzles used, the game would throw me a curveball, forcing me to deviate from previous "patterns".
Some puzzles, even of the harder variety, can be figured out quickly depending on the player's frame of mind, while "easier" puzzles (those without numerous elements) can be trickier. You know the puzzles are good when you find yourself wanting to do "just one more" before ending a session. And puzzles can often be completed in more than one way. I found out later that some solutions I used were much much more complicated than they needed to be. This dynamic of overthinking vs. underthinking is what helped make my time with "The Talos Principle" so interesting, as well as thinking out a solution before acting vs. using a lot of trial and error at other times.
This game also encourages and rewards exploration. There are stars to collect, which unlock additional content in the form of more puzzles and ultimately an additional ending choice (there's a main ending and two possible side endings). These stars are often "puzzles within puzzles" and gathering them is rewarding and can be quite challenging. It's not just a matter of "hide and seek". For example, a star may be within a puzzle and behind a door (force field). It is up to the player to figure out how to reconfigure his/her solution so that an additional door can be opened. There is also an ample amount of "Easter eggs" to find, many of which are interactive and well worth seeking out. Many are references to other games, like Portal 2 or Papers Please. Pink Floyd is honored with one as well.
Keep your eyes wide as you traverse the puzzles and worlds. Even just finding ways to exploit the simulation is fun, for example, finding a way to climb over the outer walls of a puzzle and into "out of bounds" areas (where there are some Easter eggs to find). Or "breaking" a puzzle by finding an "unintended route" to the finish by climbing over a wall, or walking above one. (This accounts for a lot of my game time).
"The Talos Principle" should appeal to a wide variety of players. I spent about 80 hours on my first playthrough and a less thorough playthrough will of course take less time. I then replaid for 100% achievements (which I usually don't do). I suspect that many of the people finishing Talos in "20 hours" are not doing everything (reading files, getting all stars/doing the puzzles they unlock, looking for easter eggs) and likely to be using a walkthrough here and there. You can play this game as you want. Complete the puzzles in order or don't. Do them fast or slow. Solve star puzzles or don't. Don't read every piece of information at the terminals if the story side of the game doesn't interest you. Look closely for Easter eggs or don't worry about them at all. Try out the side endings or don't.
The support is very good with developers active on the Steam forums should anyone have issues and updates have been released to fix and add things (like an added special settings menu for "motion sickness", a speed time function, additional language support, etc.).
NOTE: The demo is also good, yet only a taste of the full game. It ofters a solid introduction to gameplay and some clever puzzles. There is even another free game called the "Sigils of Elohim" that is made of tetromino puzzles. Solving them will reward you with codes that are then entered into the menu of "The Talos Principle" for bonuses. These do not change the core game at all but, for instance, you can get stars with these codes.
All the regular stars will still be in the game to find. If you get the codes for bonus stars (three in total), you will start with three stars in the full game. So, you'll be free to leave three stars unfound if you wish and still receive the bonus content for finding all of them. In other words, if you start with the bonus stars and then go on to find every star in the game, you will finish with an extra three stars.
PS: If you get and finish the game, check out my screenshots if you want (NOT before you play). Some hint at additional "challenges". Like getting a picture of the blue man visiting the greedy man and living to tell about it.