Looking at the various level progression paradigms for my puzzle game, I decided to rule out the common ones such as 3-star per level, linear campaign-like story, etc. I like the idea of Bejeweled's classic mode where the player simply keeps on going.

What exactly is this paradigm called? I can't find any write-ups on it so I can't quite tell what its structure is like. Is it infinite? Does the difficultly increase with each level in some shape, way or form (more likely to get "No moves")?