For the curious minds, here it is [1].
On the one hand, there is no actual progression or ramping of difficulty in the game itself. The difficulty level remains the same whether your current score is 0 or 10 or 100. But every new highscore represents a new summit that the player has to scale. The first and maybe the most frustrating summit to scale is scoring a single point. To get your score into the double digits, the player has to have basic mastery of the core mechanics - including the precise physics, and timings- and learn how to handle a certain number of scenarios. The obstacles on the path to triple-digit territory and beyond seem almost self-imposed. The fear and tension as you approach your own highscore is the biggest impediment to breaking your highscore. Once you break that highscore - the hand tremors magically disappear the next time you approach it, only for it to re-appear as you near your new highscore.
All this, when the basic concept of the gameplay is deceptively simple. Like i said, there are many layers to unpack for someone who is willing to look into it.
Asteroids is a quintessential example - relatively flat difficulty curve once you've mastered the game - it really comes down to a test of the player's endurance. Scott Safran set a record game that lasted a grueling 60 hours.
https://en.wikipedia.org/wiki/Scott_Safran
EDIT: Anyone who has EVER tried for a high score (whether a personal best, or a world record) is familiar with the natural nervousness that increases in direct proportion to how close you are to breaking it. That's not a Flappy Bird thing, that's a literal every game thing. Go watch a live stream of a speed runner that's got a heart rate monitor attached to the feed for example.
It's almost more of a game of focus or how much you will _think_, because once you're distracted a bit and forget those physics or timing just one time, you're probably done.
Nonetheless, and for the benefit of the Lucky 10,000, I must present: QWOP.