Metal Gear (NES)/Walkthrough
Metal Gear is a fairly linear game; while you are free to make your own decisions about where to go, you will not be able to access many parts of the game without taking care of prior steps first. While you may not be sure about where to go next in a given moment of the game, there is usually only one or two courses of action that are the correct choice. The challenge of the game is to figure that out.
This walkthrough has been laid out in such a way as to make it easy for you to find the section of the game that you are curious about. The pages are arranged by building and floor in most cases, along with a few outdoor sections. You are not meant to following this walkthrough in the order it is presented in the Table of Contents, or according to the order dictated by the navigation suggestions at the bottom of each page.
Rather, the game begins with the first part of the first floor of building one. When the first part concludes, the walkthrough will provide a link to the next section of the walkthrough (in this case, it would be the third floor of building one) and so on. Because you will end up visiting certain floors multiple times, those floors are broken into parts. Each part after the first contains a header indicating what steps needed to take place prior to the part in question.
While the steps required to complete the game are obligatory and may not be skipped, the order of a select few of them are optional. The biggest choice you have in the game is whether to obtain the oxygen tank first, or rescue Dr. Pettrovich first. The walkthrough the follows is one solution to the game, designed to balance difficulty and completion time. There are faster methods of completing the game, which often require taking on more challenging sections of the game earlier, and are not recommended for beginner players.
 Understanding enemy detection
Throughout the game, you will attempt to avoid enemy detection. Several actions will alert an enemy to Snake's presence, including:
- Standing or walking directly in front of an enemy's or a camera's line of sight*.
- Moving while using a cardboard box when passing in front of an enemy's or a camera's line of sight.
- Shooting or using a weapon which is not enhanced by the possession of the silencer option.
When any of these actions occurs, an alert mode is activated. When a guard sees you, they will show a red exclamation point ( ! ) above their head. When this happens, all of the guards present in the room will attack you, and they will summon backup to help them. These alert modes will end when all of the guards in the room have been eliminated, or when you run to any other screen in the building, including trucks, elevators, or adjoining rooms. Unlike the original version, there is no high alert mode that will continue on even as you move to other rooms.
* Note that all cameras have a blind spot. you can avoid detection by a camera by walking directly beneath it, or in other words, by hugging the wall that the camera is mounted to.