Those are gorgeous! Absolutely amazing, and I love how the animation is just so fluid even though it's all pixelated. Thank you for showing this! *clicks link so she can play with sliders*
The fluidness of the animation is a modern enhancement - to see how it was originally displayed on old PCs, click the "Classic" cycle mode in the settings.
Also, the technical side of these pictures is really impressive:
they were made in the early 1990s, as I have said. Back then, computers lacked the technical capabilities required to store and display complex animated pictures like today's GIFs (such file standards didn't even exist). The pictures in those links are actually not animations - they aren't a set of looped pre-rendered frames, they are static pictures. Instead, the
colour palette itself changes in a predetermined way to imitate movement. Such a technique is called colour cycling.