From Wikipedia:
A two-dimensional shoot'em up/platform game developed and published by British developer Palace Software. The game was released in 1985 for the ZX Spectrum, Commodore 64 and Amstrad CPC home computers. Players control a witch, who aims to become the "Witch Queen" by defeating an enemy called the "Pumpking".
Designed by Steve Brown and Richard Leinfellner, Cauldron originated as licensed video game of the horror film Halloween. Brown eventually altered the game to use a theme based on the Halloween holiday. The mix of two genres resulted from Brown and Leinfellner wanting to make a shoot 'em up and platform game, respectively. The developers realized that there were no technical limitations preventing the genres from being combined.
Source: Wikipedia, "Cauldron_(video_game)," available under the CC-BY-SA License.
A version of Evil Dead was also written for the ZX Spectrum but this was never released on its own and eventually appeared free with the Spectrum version of Cauldron.
Source: Wikipedia, "The Evil Dead (computer game)", available under the CC-BY-SA License.
Individual credits:
Steve Brown: design
Richard Leinfellner: design