The Talos Principle is a first-person puzzle game. Your objective is to collect sigils by completing puzzles which start simple and get more and more complex as you progress. At the beginning you might use a jamming device to move through a forcefield and need to avoid explosive robotic mines. By the end you may need to use a fan to hover a crate in the sky with a portable connector on it to link up a number of connectors around the map or record and playback your actions to carry your character round in a cooperative way to reach heights.
The world consists of a main hub and contains three worlds with seven puzzle rooms in each. Each puzzle room contains about four puzzles and up to three hidden stars. Each world has a couple extra doors that can be unlocked. Once you have enough sigils from a particular batch you use them on their intended door and have to play a shape fitting puzzle which ultimately unlocks the door.
At the beginning you are prompted by a god-like voice to complete puzzles with the purpose of ascension. The voice forbids you from climbing his tower. Later you begin to interact with an entity who prompts you to defy the voice and pushes you into climbing the forbidden tower.
As you explore the world you uncover story elements by finding terminals containing documents and communication from the human world. You also have some interestingly heavy discussions about what it means to be conscious.
The graphics are pretty good, the game uses the same engine and shares a lot of the same assets as Serious Sam 3: BFE. The sound is also pretty good and includes relaxing music. The god voice that speaks to you throughout the game is voice acted.
Occasionally I got the impression I wasn't completing a puzzle in the correct way doing it without using all the tools available or in a peculiar feeling way (I could be wrong). Beyond that, I didn't encounter any bugs or problems during my play through. The game is very well polished and must have been through some serious testing.
I've completed the game in sixteen hours and collected almost everything on the way.
Other than Portal, I can't think of many games similar to The Talos Principle, and much like Portal The Talos Principle is excellent. Highly recommended.