Heavy Metal

Heavy Metal is an achievement in Metro 2033.

Overview
This achievement is awarded for obtaining a kill count of 15 whilst using a Mounted Machinegun. The kills can either be obtained on human enemies or on mutants and has to be done in a single playthrough of the story.

A stationary machine gun can be used in the following locations:
 * Cursed - Usable by the player and is an effective weapon for defending from the mutants.
 * Frontline - Several of them are found, all are usable but only one is advantageous.
 * Trolley Combat - Mounted on the rail car, as it is the only weapon in the level.

Trivia

 * The achievement's name is referring to the stationary machinegun as it is the heaviest weapon in the game and that it fires the heaviest ammunition.
 * The name also refers to the music genre of the same name.
 * The achievement icon is a belt of 12.7x108mm rounds which is the type of ammunition that the stationary machinegun fires.
 * Vehicles will not count toward this achievement, including the Panzer, the crews in it count though.