Sharpshooter fallacy: shooting a rifle at a barn and painting a bullseye around the biggest cluster of hits.

"Portal is to a great extent a tech demo" (therefore it shouldn't be judged as a game)

Yet Portal is sold as a game in its own right. Riven was released in 1997 and is still a delightful intellectual challenge today, with nothing really like it. It's very much the opposite of modern games with a built-in GPS system telling you where to go. Riven is clunky, pixellated, but integrates good puzzles and a well thought out world in a way I haven't seen anywhere else. It was also a technical feat at the time.

Like I said in my Steam review, I believe Portal popularity comes from the fact it's a puzzle game attractive enough to draw people who don't play puzzle games.

Baba Is You is going to be a classic 20 years from now, despite its ugly graphics. In hands of anyone else, it would be just a gimmick, like Portal. But the idea was masterfully executed.