Gurumin: A Monstrous Adventure is a 3D platform game with action and adventure elements. It stars Parin, a 12-year-old girl who moves to the mining town of Tiese to live with her grandfather, the mayor. Her parents are on an excavation overseas. Parin feels lonely until she discovers a monster named Pino being attacked by a stray dog, which she rescues. This leads her to meet other monsters in Monster Village and find some friends.
Parin soon learns that Puku, one of the monsters, has been kidnapped by evil creatures called phantoms . Parin must rescue him using a legendary drill given to her by her new monster friends. The phantoms attack Monster Village, putting the world at risk. Parin must navigate through dungeons to restore Monster Village and save the world.
The gameplay involves platforming with puzzle elements, as well as combat against enemies. Parin's drill has four power levels that build up or decrease depending on her progress. She can also equip accessories with various abilities, such as increased defense or more coins.
The game features two forms of currency: coins and junk. Coins are easily found in pots or dropped by enemies, while junk is acquired from enemies carrying items like shields. The goal is to collect enough resources to upgrade accessories or learn new attacks.