is there any specific colour palette that you used, or is it hand-picked?
Most of my assets strictly follow the NES's limitations, so the palette is the NES palette: https://lospec.com/palette-list/nes-aesprite. Each tile uses one of several sub-palettes that are made up of 3 unique colors and one shared color. Same goes for the sprites with the shared color being the alpha channel. Hope that helps!