Im pretty new to this style. Comment and Critics, please.
Program Used: Gimp 2.6

WOW!
Nice texture Raiken
It look like Power ranger mask

I Think You Should Raise The Red Thingy But Its Amazing

I don't really like the shuriken thingy upside the visor

But Its good tho, pretty good shading

Hmmm I think the Black lines are a way too intense, if you know what i mean.
Maybe use a darker grey or smt. like that.

almost the same head

If you're talking about the colors.
Yes.
I added some darker white tho.

It feels empty
Give the back of the head as much love as the front
Put some red back There
Or come up with an appealing Design in the back that keeps the compisition flowing
For me theres Not enough of a contrast between the White and grey

One thing. We humans have our eyes vertically in the middle of our head. I always think it's a cringe if people doesn't put visors/eyes there on the tori either.
Bring it up a notch.

Also, I don't see anything really original here. Try to be slightly different, and try a new approach!