While there may be no doubts as to whether or not Gwen Stacy is dead, (she is) there appears to be a few unresolved issues concerning this near 30 year old storyline. One is, which bridge was it? The George Washington Bridge, or the Brooklyn Bridge? Another issue is, did Spider-Man kill Gwen? Or could it have been the shock of the fall? Well, here is where we set the record straight for everyone out there, no ifs, ands, or buts about it.
First off, which bridge? In the original script, Gerry Conway writes the soon-to-be-famed location as the George Washington Bridge, (As that is what Spider-Man says) however it is my opinion that artist Gil Kane made a slight goof and referenced the wrong bridge, in effect drawing the Brooklyn Bridge. Now, in doing a little research, the earliest known retcon I have found (so far) is in Amazing Spider-Man #147 (only 26 issues later) where Gerry Conway himself, the original author, writes a story in which the Jackal plans to throw Spider-Man off the same bridge where Gwen Stacy died. On page 27, first panel, Spider-Man himself says "It's the Brooklyn Bridge!"
While a few later stories referencing Gwen and the bridge might have slipped up and mentioned the George Washington Bridge, (What If? Vol. 1 #24, What if Spider-Man had rescued Gwen Stacy) the truth is, nearly every future reference in the Spider titles will say the Brooklyn Bridge. Even in later reprints of Amazing Spider-Man #121, the name of the bridge has been changed! You can see this for yourself in the provided images. Now WHY is it, that when I read current material referencing the death of Gwen Stacy, such as the DK book 'Ultimate Guide to Spider-Man', and 'Behind the Mask of Spider-Man: Secrets of the Movie', the authors will STILL say George Washington Bridge! Its uncanny, as this was attempted to be straightened out by Gerry and Marvel at least 27 years ago!
So now that you are aware of the details, this issue is closed. The bridge where Gwen Stacy died is the Brooklyn Bridge.
Thats one down, one to go! It seems to have been a big debate on how Gwen died. Did Spider-Man kill her? Whats up with the *snap* when Spidey snags Gwen with his webbing? Was it the shock of the fall? Well, if you have Amazing Spider-Man #125, check the letters page, and you will find your answer. I believe it may have been Editor Roy Thomas who penned this, but it shouldn't matter as the response comes from Marvel. Here is an excerpt of Marvels response as printed in Amazing Spider-Man #125:
First, for the many who wrote and complained that the fall alone could not have killed Gwen if she were unconscious (and therefore unable to be scared to death, the usual explanation for a person dying before hitting the ground), it saddens us to have to say that the whiplash effect she underwent when Spidey's webbing stopped her so suddenly was, in fact, what killed her. In short, it was impossible for Peter to save her. He couldn't have swung down in time; the action he did take resulted in her death; if he had done nothing, she still would certainly have perished. There was no way out.
So only a mere 4 issues later, Marvel themselves resolved that question. No, Spider-Man did not kill Gwen, Spider-Man tried to save her. Much in the same way a surgeon tries to save the life of a gunshot victim, but if the patient dies, the doctor isn't the killer, the gunman is. If the doctor had chose to do nothing, the victim surely would have died anyway. Gwen Stacy's true killer is none other than Norman Osborn, the Green Goblin.
I hope this finally lays to rest questions that still appear even today, but were obviously addressed so long ago. I guess it just goes to show you, in light of such a shocking, fantastic story, sometimes you overlook the details that come out later.