Depends on your definition of fun. In both Braid and the Witness, eventually you come across a puzzle you cannot solve and have to use Google to find the answer, because the game never bothered to even hint at how it could be solved.
That's pretty much the opposite of fun. Just pretentious; I would expect more of the same.
My wife who had never played a video game beyond Pokemon played both of those games and completed them with no assistance, as did I, so I'm not sure what you're talking about tbqhf
Blow has actually talked about those puzzles in streams, said he regrets it because more players than not stopped playing the games at that point. It's the definition of bad design to implement some untested abstract idea without giving the player any hints.
There are no hard puzzles in Braid, at least not that are required to beat the game, so not sure what you mean. I never played the witness so I don't know about that game.
There is one puzzle piece that you can't reach early in the game; to get it you have to bring a later piece back to the puzzle, put it in its place, then jump on the platform that is drawn on the puzzle piece.
But most people just give up in frustration trying to reach the piece because the game hasn't given you enough information to know you need come back for it later.
Braid also has the stars which are so well hidden that I can’t imagine anyone finding them without a walkthrough (though some people obviously did in order to make the walkthroughs).
The Witness is different, it really does teach you everything you need to 100% it. I cheated on the ship puzzle but it’s totally possible to figure out.