The Mummy Demastered is a licensed tie-in to the 2017 film The Mummy, which starred Tom Cruise and Sofia Boutella. Rather than follow the plot of the movie directly, the player assumes the roles of various members of the Prodigium paramilitary unit headed by Dr. Jekyll (played by Russell Crowe in the movie) in a story that runs concurrently with the movie's events. Prodigium's goal is to defeat the minions of the antagonist Princess Ahmanet (Boutella).
The Mummy Demastered spiritually follows from WayForward's similar attempt to find a compelling 2D outlet for licensed material with Aliens: Infestation, based on 20th Century Fox's Aliens franchise. Similar to that game, The Mummy Demastered is a metroidvania-style action-platformer with a respawn system where, instead of restarting with the same character from the last checkpoint, the player takes on a separate member of the same unit who must defeat their now-zombified predecessor to recover their gear.