You can see that my color is more cel-style than the original. This is because importing rasterized files into Flash increases the size of your animation, which makes for a longer download time; if you're drawing your character in Flash, you'll have an advantage there, as yours will be vector-based and won't take up so much space. It will also resize cleanly, while rasterized files will pixelate.
Keeping your color simple will reduce your filesize. The color is also simple because there are places where the lines don't join seamlessly, and instead end in open areas of color. That color will need to mesh together when I reassemble Lex, so it's better to keep it as simple as possible. So I went with three shades on each color--one primary color and two variations of shadow on matte parts like the jeans, and one primary, one highlight, and one shadow on glossier objects like the skin or eyes. The only place where I deviated from this was the hair; I used a primary, a highlight, and a shadow, and then added a few touches of white. Notice all colors are in block shapes.


