Clash at Demonhead, known in Japan as Dengeki Big Bang! (Japanese: 電撃ビッグバン!, Hepburn: Dengeki Biggu Ban!, Blitz Big Bang!), is an action-adventure platform game released by Vic Tokai for the Nintendo Entertainment System on January 27, 1989 in Japan and January 1990 in North America.

Clash at Demonhead is an open-ended platformer. The player takes control of Billy "Big Bang" Blitz, who is capable of running, jumping, and shooting. He is initially armed with a handgun, though various upgrades can be purchased from a shop, such as the boomerang gun. He later gains the ability to perform various powers by collecting Force, including shrinking, teleportation to previously-visited areas, flight, healing, and invincibility. The game is divided into a number of smaller stages, each representing a point on the over-world map. There are over 40 routes the player can take in the game, and the player must explore the world to progress. The game is non-linear in that the player can choose which direction they go, being allowed to backtrack and visit different stages.