I know I've said this before, but one of the biggest challenges working with X's sprites is that X simply doesn't have any good standing sprites. All of his sprites from the games have him all hunched over, ready to fight and/or in the process of fighting. I did what I could, but what you see here is the best I could do with my meager spriting skills. Thankfully, DisgruntledFerret came along and made some excellent X sprites that I would use in future storylines.
As far as Zero go, his X3 sprites don't offer much for standing either, but he does have some decent X2 sprites. For example, in the first three panels I messed a bit with an X2 sprite, such as adding his X3 hair, to make it match a little better with his X3 sprite in the last panel. In fact, if you look closely, you can notice some differences in texture and coloring between the different sprites.
And in case you were wondering, yes, that's the same bit of hair I used on Roll's battle suit.