Infinite materials? You can!
We have already talked about the Mother Base and its development in this guide, but today we want to help you develop the skills of Snake and his weapons, helping you to have fuel and metals practically infinite!
All you have to do is repeat the main mission number 12; when you are inside the underground base and after watching the cutscene of Otacon e Skull Face, just eliminate the soldiers in the area and go up the stairs. At the top, you will find 2 containers containing both fuel and metals. The only flaw is that, in order to use it, you should have unlocked the upgrading of the Fulton system which will allow you to "ship" even the heaviest objects (the containers themselves) to Mother Base.
To get this upgrade, it will be necessary to continue in the game for the level of your Mother Base to rise, and to capture with the Fulton system an enemy equipped with the specialization in transport. Once these requirements are met, the upgrade will be yours, and you can have an infinite amount of materials, replaying the mission.