The player controls a robot, the starting robot is a very basic model, to which the player can add "improvements" with credits earned during gameplay. There are four areas that each robot is graded on, body, left arm, right arm, and legs. There are several different combinations of various parts that can be added to the player's robot for optimum fighting status. During a fight, each area mentioned above is represented by its own health meter. The objective of the player is to deplete the health meters of each area.
Source: Wikipedia, "Metal Masters", available under the CC-BY-SA License.