Midday-Mew's Sprite Thread

[Midday-Mew]

Attempted to do a Mewtwo head in 4-color limitation. Side note: where I'll be using this sprite will be on a black background and will not be displayed at 1x.

I think I didn't do so well.

I need to do a Mewtwo head, a Lucario head, and a Charizard head, at the smallest possible size, and in grayscale. I'm pretty nervous about having to do it because I can't sprite most Pokemon to save my life, much less at such a small size.

Please critique and please suggest how I can revise this sprite to make it look more like a Mewtwo head?