Gray Matter is a third-person mystery adventure game. There are two playable characters, namely Samantha Everett, a street performer, and Dr. David Styles, a neurobiologist. In the story, the reclusive Dr. Styles is undertaking a research in his estate called Dread Hill House. Samantha gets involved as his assistant. As the story progresses, unexplainable things and supernatural events begin to happen. For a start, Dr. Styles gets a visit from the spirit of his deceased wife. There are more mysteries in the mansion, and it is up to Samantha and Dr. Styles to solve them.
As a research assistant, Samantha’s first task is to find willing volunteers for Dr. Styles’s experimental research. Taking on the role of Samantha, the player will have to use magic tricks to do accomplish her tasks. The game has eight chapters. In each chapter, the player is presented with a set of objectives that must be met. The game features a number of different puzzles, including word fames, mazes, riddles, visual puzzles, and Samantha’s specialty: magic tricks. Players have to get tricks from Samantha’s book and apply these to solve puzzles and finish challenges.
Magic tricks are the major gameplay elements. The player will be controlling Samantha most of the time and will also control Dr. Styles in some situations. There are areas that only Samantha can access; the same goes for Dr. Styles.