I hadn't realised there's a demo of the sequel out already - downloading now... But yeah, the videos on the steam page look absolutely amazing, clearly lots of new mechanics etc. If they can get it to get close to the quality and inventiveness, we're in for an absolute treat; seems unlikely they could surpass it, but who fricking knows, I've got a feeling this could be something pretty special.
The Talos Principle
OG came out in 2014 - there are deluxe editions now (nice graphics and frame rate, plus the DLC). Highly recommended for folk who like puzzlers. Metaphysics in there too, stars for even more crazy invetiveness, but the basic puzzle learning curve is itself just supremely handled. Such simple mechanics, such great combinations. Often available for just a few quid, on all the major systems.
Played enough of the demo to say this feels proper legit. Overworld is quite different, but new mechanics seem fun, and looks like a good amount of content in and out of puzzles.