It is not a 1-bit game.
Maybe it is a 4-bit game, because in 1-bit games have to use only 2 colors, but there is more than 2 colors. Ok? So this game isn't 1-bit game.
You can still apply different palettes to different elements on the screen, even if each element only uses 1 bit per pixel. It just means that each palette can only have two colors.
