The corner of a difficulty curve often becomes a quitting point, partly because it is a change in the game, partly in the way an extreme one feels like a betrayal of the relationship the game had been establishing, and sometimes because it indicates the developers are not very good. While Portal perhaps goes too far in making the first half+ of the game a gradual tutorial, it does have that transition into “and here are some harder puzzles, and now you’re on your own.” Do you have a favorite example of a game that says, “here are some tutorials, and now we’re jumping straight to the highest difficulty”? The Witcher 2 is notable for making that jump before completing the tutorial. Either the developers did not recognize that they turned the dial from 2 to 8 or they thought that was a good progression, and neither implies, “these people probably made good design decisions in other areas.”
: Zubon