Cool , i tried gameboy style too, IMO pixel art is hard because you have to know contrast and volume/shading, i dont do that when im animating so my anims look flat.
I think to be good at sprites/pixel art you have to be great artist and know colors, shadows,highlights and all that.
Funny thing is (or sad) that i would not pursue pixel art to create my own characters cause i struggled with it too much, so i found other way to animate characters and now i can draw whatever i want.
Yes it is in my style that is not as appealing as some actual pixel art but it still encouraged me to create more and gave me hope.
Learning pixel art , decent pixel art is HARD even if you can paint and know colors.shadows and light.