CarnEvil is a light-gun shooter game in which the player, as an unnamed teenage everyman,[1] must clear four levels by eliminating waves of various gruesome creatures such as evil clowns, sideshow freaks and Krampus's elves.

[2][4] In the fictional town of Greely Valley, Iowa, an urban legend claims that if a golden token is inserted into the mouth of Umlaut, a jester's skull on top of the gravestone of a ringmaster named Professor Ludwig von Tökkentäkker, his haunted carnival will rise from the earth.

Although Haeger was aware that technical limitations at the time made the concept impractical, he saw potential in the "dark carnival" theme.

[1] Midway Games approved Haeger's concept following the successful releases of the light-gun shooters Terminator 2: Judgment Day (1991) and Revolution X (1994), which Haegar co-directed.

After this version was harshly reviewed by Midway's management, the development team revamped the concept with characters that were more aggressive and darkly humorous.

This tone was set by Haeger's conceptual character Hambone, a large brute with a goaltender mask and a gatling gun arm who would become the miniboss of the Haunted House stage.

[5] Jason Wilson and Tyrone Rodriguez of Tips & Tricks also praised the graphics, writing that "the stunning 3D environments are portrayed in such gruesome detail, you will think you're trapped in a horror film".

[4] French magazine Player One gave the game a score of 69%, regarding it as a House of the Dead clone, but commending the gun's design and precision as well as the gory graphics.

[10] According to Haeger, the game's sales exceeded those of Mortal Kombat 4, which encouraged Midway's arcade team to conceptualize a 4D ride adaptation that ultimately never materialized.

[10] In September 2015, the fansite "Greely Valley Cemetery" was created as an archive for the game's concept sketches, promotional art, music tracks and voice clips.

Lucas Sullivan of GamesRadar+ considered Killing Floor and its sequel to be spiritual successors to CarnEvil, and he saw a thematic influence on the "Loony Park" level in Painkiller's Battle Out of Hell expansion pack and Until Dawn: Rush of Blood.