Streets Of Rage 4 — Mr. X Nightmare is an add-on for the old-school side-view beatmap Streets Of Rage 4. After the events of the original game, our heroes decided to prepare for further threats. Axel, Blaze and their friends will begin a special, crazy workout. Dr. will help them with this. Zan, who developed an artificial intelligence program based on the surviving brain cells of Mister X and capable of simulating any potential danger.