Actually, it's a surprisingly fun game. Though Skeleton+ is a lot better. Ammong other things, it has dificulty settings.

I'm not aware of any games that used all of the colors at once. But many would scroll through all the colors. Though that doesn't really count since it's only showing a few at a time. The colors were used to make sky backgrounds on some games. You could look to the horizon, and there's like 20 different colors just to show a sunset or something. One of the nicer looking effects on the system.