For those who don't know, Gwen Stacy suffered a tragic death in "The Amazing Spider-Man" #121, after she is thrown from a bridge by Green Goblin, with Spider-Man failing to rescue her. While grabbing her before she fell, his webbing created a whiplash effect, snapping her neck.

Gwen Stacy died due to the whiplash effect caused by Spider-Man catching stopping her fall too quickly mid-air. Gwen Stacy was hurled off the bridge by Green Goblin, and in an effort to save her from certain death, Spider-Man shot the web, caught her feet, and pulled her up, realizing she was dead.

As fans know, Gwen Stacy was killed when Green Goblin threw her off a bridge to torment Spider-Man in the main continuity. Peter tried to save her with a webline, but the sudden whiplash of her abrupt stop snapped her neck, and the guilt has haunted Earth-616’s Peter ever since.

Gwen Stacy died in Amazing Spider-Man 2 because she had already died in the comic version. Gwen was killed off in the pages of The Amazing Spider-Man comic issue #121 published in 1973. While many comic book characters often come back to life, she was never resurrected.

Having discovered Spider-Man's identity, the Green Goblin abducts Spider-Man's girlfriend Gwen Stacy. Gwen is killed during the battle, and a subsequent fight results in the Goblin's death.