- Size should be about 2 pixels smaller.
- The shape of the mask is horrible, espacially at the bottom. You should try to make it smoother or redo it.
- The shading is bad. The mask doesn't look metallic (I mean the white part, obviously). Use light grey as a base color and white as highlights for a metallic look. The blue side should have nearly no shading at all, just some AA.
- The shape of the eyes is a bit odd. Try to make them more vertical than horizontal.
- The visor looks jagged. Remove that grey/dark blue border around it and use AA.
- I think you should not make those spike things at the top so noticable.
I hope this will help you a bit. I could also try to make an edit if you want.
- The shape of the mask is horrible, espacially at the bottom. You should try to make it smoother or redo it.
- The shading is bad. The mask doesn't look metallic (I mean the white part, obviously). Use light grey as a base color and white as highlights for a metallic look. The blue side should have nearly no shading at all, just some AA.
- The shape of the eyes is a bit odd. Try to make them more vertical than horizontal.
- The visor looks jagged. Remove that grey/dark blue border around it and use AA.
- I think you should not make those spike things at the top so noticable.
I hope this will help you a bit. I could also try to make an edit if you want.