Sure, that's true, but when they were coming up with the design for the movie, I bet they referenced the Giger Alien in their discussions on how to approach Venom live action, and thought that if that design worked onscreen, then they could do a straight transfer of the comic book image, with the shiny 'helmet' aspect, and the head being less human in shape.
edit: That first design is more like that aspect of the giger design, with the shiny 'helmet' that protrudes from the alien head, with the large gaping jaw below it. It only very basically resembles the shape of a human head, so it would look funny on a human body, but looks fine when Venom is crouching.
So, they went with a more human shaped head, and made it less shiny, losing that aspect of the comic image and giger design.
Y'know, I'm just guessing at their discussions, but I would be very surprised if the Giger Alien design did not come up in discussions along those lines, that's the kind of thing that happens in these kinds of things.