Ralph Bagley, N'Lightning's founder and chief executive officer, conceived Catechumen in 1996 because he had mixed feelings about playing Doom and Quake as a licensed minister.

He was unable to obtain funding until the Columbine High School massacre in April 1999, which was partially blamed on violent video games.

That month, Bagley established N'Lightning, raised US$1 million, and hired staff from the recently defunct Trilobyte to form the core design team.

Catechumen received mixed reviews, with praise for its fast-paced action and differing opinions about its story and audiovisual presentation.

The player assumes the role of a catechumen, a novice Christian undergoing training with a mentor for one year before being granted access to secret meetings.

They shoot energy beams that defeat demons and convert Roman soldiers to Christianity, who then kneel down and start to pray.

[2] Some levels require the player to solve puzzles to proceed, such as finding keys, pushing buttons or levers, turning valves, and rearranging boxes.

[2] There are five difficulty settings—"Fledgling", "Easy", "Normal", "Hard", and "Impossible"—and beating the game on the highest setting unlocks the secret "Hall of Fame" area.

[4] The company's founder and chief executive officer, Ralph D. Bagley, was a licensed minister at the Church of God in Christ in Medford.

[15] At the same time, Trilobyte, a local game studio that had developed The 7th Guest and The 11th Hour, had recently closed and laid off its staff.

[8] Initially aimed solely at other Christians, the game was later designed for a wider audience by not being "preachy" about its biblical themes and texts.

[2][19] FindEx, a software distributor with a focus on Christian media, was tasked with shipping it to store chains like CompUSA, Wal-Mart, and Babbage's.

[29] CNET Gamecenter's Colin Williamson lauded the game's pacing, saying it was "ridiculously fast, making even Doom seem lethargic in comparison".

[28] A.S. Berman, in his review for USA Today, reported the game as a satisfying adrenaline rush, and he praised the environments as being "exquisitely rendered".

[31] Randy Sluganski of Just Adventure said the graphics were less advanced than peers like Quake and Unreal but praised the use of vibrant colors, dynamic lighting, and volumetric fog.

[29] Ryan Reynolds wrote for the Evansville Courier & Press that the game exhibited some visible shortcomings, such as enemy limbs clipping through walls.

[11] Catechumen and Ominous Horizons were among the bestselling Christian games of all time, and N'Lightning's sales increased yearly.