Metal Slug 6

Metal Slug 6 returns to the alliance between Rebels and Martians from Metal Slug 2, X and 3, but on a much larger scale. Instead of repeating the events from the previous games, where the Martians broke the alliance and the Rebels helped the player in return, the player now joins forces with the Rebels and the Martians to fight an even bigger threat. Metal Slug 6 introduces a new game mechanic called the "Weapon Stock System". Two weapon power-ups can now be carried at the same time. Players can switch between the two weapons or put both away in favor of the default weapon. When you receive a new weapon power-up, it automatically takes the inactive slot or, if both are holstered, replaces the less current weapon. The score is now multiplied by a power of 2. The faster the enemies are killed, the higher the power, as indicated by a display at the bottom of the screen. When the indicator shows "Max", enemies and destructible objects drop coins for an additional high score.