He made a darker shade of the main green for big shadows; the entire lower body is painted that color. He then made shadows for that green.
He also did highlights by the same recursive process.
The hues aren't consistent because shadows are usually bluer, and highights are usually oranger or yellower or whiter -- you have to play with it, but I think that's a reasonable rule of thumb.
He's also using highlights and shadows to suggest new outlines or replace outlines he's drawn.
And you're right, explaining all that would have been fair. I think it's a big much to expect "how to make a 16x16 sprite" tutorial to include "how to paint/draw", though.
He made a darker shade of the main green for big shadows; the entire lower body is painted that color. He then made shadows for that green.
He also did highlights by the same recursive process.
The hues aren't consistent because shadows are usually bluer, and highights are usually oranger or yellower or whiter -- you have to play with it, but I think that's a reasonable rule of thumb.
He's also using highlights and shadows to suggest new outlines or replace outlines he's drawn.
And you're right, explaining all that would have been fair. I think it's a big much to expect "how to make a 16x16 sprite" tutorial to include "how to paint/draw", though.