Atari 2600 Horror: The Texas Chainsaw Massacre (1983)
In 1983, Wizard Video started a short-lived division called Wizard Video Games, capitalizing on a brief boom in third-party Atari games that started with Activision's defeat of an Atari lawsuit in 1982 and ending with the the video game crash of 1983. Wizard only managed to release two games, both based on iconic horror films: The Texas Chainsaw Massacre and Halloween (a game adaptation of Flesh Gordon was also planned, but never released); they were the very first horror-themed videogames (I'm not including Atari's Haunted House, alright?).
After seeing the screenshots below, you might be surprised to hear that parents protested these games due to their bloody content. Many stores complied by removing the games from their shelves, but still kept them behind the counter with other adult Atari titles (such as Mystique's Bachelor Party and Gamex's X-Man). The result was extremely poor sales of the Texas Chainsaw Massacre cartridge, followed soon after by the sad demise of Wizard's videogame division.
The game is a one-player side-scroller that requires you (as Leatherface) to kill all those in your path before your chainsaw runs out of fuel. As you approach your victim they release a high-pitch tone (that's their scream). You can rev your chainsaw before chopping them up, but this uses up your precious fuel. Obstacles include wheelchairs, gates, brambles and cow skulls, separated by long stretches of bright green grass. There is only one difficulty setting.
Wizard hired a firm called Games by Apollo to create the actual code for The Texas Chainsaw Massacre game. Programmers Mark Klein and Ed Salvo spent six weeks building it, during which time they watched the film for ideas to incorporate into the gameplay (apparently none of those involved had seen it before). Salvo later said that he wasn't proud of the end result; he would go on to help create more successful games for Apollo, including Spacechase and Lost Luggage. Klein created another horror videogame adaptation later that year for The Entity (which was never released due to its controversial content), as well as the popular Subterranea game and others.
An alternate, unreleased version of the Texas Chainsaw Massacre game has recently surfaced, although it's not clear if it was also programmed by Salvo and Klein. It takes a somewhat different approach by allowing Leatherface to create mysterious rainbow blocks with which to trap his victims (I'm serious) before attacking them with his chainsaw. It also allows two player gameplay - the other player controls the victim, who can shoot back at Leatherface with a gun.
The TCM cartridge is classified as a rare game and can be difficult to find. There are currently none available on eBay, but apparently a copy still in the box can fetch upwards of $300. Fortunately, the ROM for the game is easy to find and can be used with any Atari emulator.