Metal Gear 2: Solid Snake is the 8-bit Japan-only sequel to Metal Gear. The game takes place four years after the events of the first game. The premise is that the now-retired Solid Snake is hired to infiltrate the territory of Zanzibar Land in order to rescue a kidnapped hostage to prevent the creation of a second Metal Gear. The gameplay is similar to the original, however many new features were added such as the ability to kneel and crawl. The enemy guards in the game have been improved, whereas in the previous game they could only see in a straight line; they now have a vision arc of 45 degrees.