Formors first phase will involve it firing its main cannon, autocannons and running over the player. In its second phase, after losing half of its health, it will also try to jump on top of the player.
As this tank attempts to run over the player, its bottom is revealed exposing a weak point, as indicated by a minor explosion every time it gets hit there, allowing the player to deal extra damage.
Due to its low health, Formor can easily be beaten by using the Metal Slug or Shotgun acquired earlier in the level. Moreover, the player can also simply use grenades and the handgun. The Black Hound, Armor Piercer, and Crawler cards are also effective and will make short work of this boss. Defeating Formor again in a fast time will unlock its Card.