In Machina Arcana, players take on the role of explorers who are investigating an ancient subterranean complex of unknown origin. They face monsters inspired by H. P. Lovecraft's Cthulhu mythos in a steampunk setting. The adventurers collect equipment, interact and utilize their environment, fight monsters, and immerse themselves in the rich narrative elements.

The complete story is broken down into different scenarios that represent a self-contained game. All of these scenarios contain chapters, each with its own narration and specifics. The objective of the game is to progress through the tale and face the endgame at the finale of each scenario.

The main goal behind Machina Arcana is to provide players with a chilling game that can never be played the same way, mechanisms that enable varying strategies and approaches, and an extensive framework that combines everything smoothly. The game scales by default; there is no need for special conditions based on the player count. As the story progresses, so does your gear. But beware! If you are too slow, horror might very well prevail and devour you whole.

The 2nd edition has a lot of improvement to the rules; as well as a new manual, new illustrations, new graphic design, and additional content. The 3rd edition includes no rule changes aside from rewordings to make the game more easier to understand, and to help the new players with the learning curve. But, the 3rd edition is the first one to offer other languages than English: French, German, Polish, and Spanish.