Yea been doing a little research to figure out what's wrong.
I don't know photoshop so this is my only means of explaining what I see to be fixed.
The visor area has two sections or steps on the side, (top and bottom) bottom flowing into the air intake. On screen helmet it's broken into approximately 2 equal lengths (top section almost equal to bottom section, maybe 2/5 3/5), on 1/6 top section is about 1/3 of the bottom, which drops everything lower giving the elongated look. Air intake (ear) is also longer due to this than original.
The mouth piece (or grey part) is smaller in screen helmet with bigger black outline. The 1/6, if you notice the flat part on top is again 1/3 to 2/3 of the lower part with square area and round faucet screen thingy.
From what I see, these combined give it a longer, dare I say "horse face".
Nicely done. You should send that to Sideshow.