I'd make them look at 8-bit art blown up and I'd discuss cluster theory. I'd change a few pixels in iconic sprites to show the results. If they can understand banding and how to solve the problems it creates, they'll see the 'puzzle game' aspect of pixel artistry, that is style-neutral and of use to any pixel artist.
That's quite a nice idea and would show one of the most basic and timeless concepts behind the artstyle.
However I can imagine if there is a class filled with people who are new to pixel art all of them have a very different approach to the artstyle, even if all of them are gamers.
A lot of people however don't know in which forms pixel art can appear. Even if you just look at arcade automates there can be a huge difference
e.g.
(Donkey Kong Arcade, Metal Slug 3)
nonetheless in terms of the pixelation point of view both are pixel art.
modern pixel art games which work with a lot of gradients and cool lighting stuff are also considered as pixel art, although we from Pixelation usually take distance from those concepts.
Is it pixel art? I'd say it's enhanced with a few modern concepts, but yeah it's still pixel art even if there are gradients, resolution mitchmax etc.
This definitely also should be considered, since Swords&Sworcery is a very modern approach of "pixel-art" or at least it's pixel art how a lot of indie developers see it today.
So giving your people an actual understanding how vast the difference of the visual styles is might get more of them interested.