[mjn]

Some demos have interactive components I believe, though I'm having trouble digging up a prominent example at the moment. Not as games per se, but in the sense that the graphics/audio can change procedurally in response to keystrokes.

As far as non-interactive demo-style stuff, markets pop up occasionally for procedural/generative art, which is related, though again with less focus on compactness (except when necessary). There was a market for screensavers in the 90s, for example, and some had pretty involved procedural stuff going on. Today there are a handful of mobile apps doing generative graphics, e.g. http://superfiretruck.com/iteration/. I think you could probably sell a demoscene production or demo-pack on Android.

[Jare]

Our Heartquake back in '94 had a flyby sequence over a voxel landscape. The path was predesigned, but you could take control at any moment by pressing keys or the mouse. I thought more demos would incorporate such optional interactivity in more subtle ways and more types of effects (ours was kind of obvious), but it didn't happen.