Dr. Chaos

A scientist named Gene Chaos is conducting a series of experiments in a country mansion. As a result, portals to other dimensions open throughout the house, from which all manner of evil begins to emerge, and the scientist himself disappears. Michael Haos, the younger brother of the missing man, must explore the mysterious mansion, fight monsters and solve the mystery of the doctor's disappearance. The gameplay is divided into three parts: travelling along the corridors, exploring the rooms in search of transitions to another world (the action switches to a first-person view and you will have to work hard to find secret passages through fragile walls), and finally visiting dozens of zones of parallel reality. The hero will have a series of weapons and tools at his disposal to help him along the way. Not a bad project for its time, with a dark world and varied gameplay.