Omicron variant or Just a Game:OmikronThe Nomad Soul

You've got to watch this Omikron!!!!

Omikron: The Nomad Soul (known as The Nomad Soul in Europe) was released in 1999 for the PC and Sega Dreamcast. It featured David Bowie in two cameos

Responding to the desperate pleas of a mysterious character from another dimension, your soul must enter the dark and futuristic city of Omikron. This is but the beginning of an epic adventure through an increasingly strange and dazzling parallel world. You must solve the ultimate mystery: why are you in Omikron and how can you get out? Think, fight, and interact with awe-inspiring environments to defeat the menacing demons that are trying to stop you. Experience the life in an alternate reality with everything it has to offer--including the secret musical performances by The Dreamers, a band of rebels led by the Omikronian incarnation of David Bowie.

"The planet is going through a terrible glacial era, and the extinction of its only sun has rendered all life on the surface of Phaenon impossible. In order to survive the eternal night and permanently freezing temperatures, the population has taken shelter in five cities, each encased in a crystal dome.

At the time of your arrival in this universe, a gigantic central computer known as Ix presides over the city of Omikron. In its virtually infinite memory are concentrated all of the data from the entire galaxy, collected by its numerous sensors. Using this information, Ix is better able to manage the interests of the human race. But Astaroth, prince of the demons, has bigger plans. He secretly seizes the Ix computer and swears his revenge. He vows to conquer not only this planet, but also spread his reign over the entire universe, to avenge himself of those who chased him away."
— Official Description

Story

Soon after the beginning of the game's introduction, the player begins the investigation in the Anekbah sector. He uncovers information that suggests the serial killer he is looking for is in fact not human but actually a demon. When members of an apparent underground, anti-government movement contact the player and confirm his suspicions, the investigation deepens and uncovers information; one of Omikron's chief police commanders, Commandant Gandhar, is a demon pretending to be human and lures human souls into Omikron from other dimensions by way of the Omikron video game. Kay'l 669 asking the player to help him was a trap: supposedly, if the in-game character dies, the real human playing the video game will lose their soul forever. Despite many assassination attempts on the protagonist's life by other demons working behind the scenes, the player destroys Gandhar with supernatural weaponry.