I'm only learning, so don't hit me hard, please... ^_^
Used: 8 colors; 64*128 size.
Optional rules wasn't used.
Maybe try using more distinct shades if you are going to shade it, personally i could really only see 4 colours until i zoomed in quite a bit
Maybe try using more distinct shades if you are going to shade it, personally i could really only see 4 colours until i zoomed in quite a bit