An outpost on Pluto has been destroyed by a malfunctioning laser weapon in 2391.
In this game, the player controls the M-368 Gunner, who storms into the defense base in order to activate the self-destruct system before the laser gun destroys the planet.
MetalStorm's main feature is the ability to flip between the floor and ceiling using the M-398's gravity control device.
Six stages, each with two acts, and a boss rush stage are featured in Metal Storm, an action-platform game for the Nintendo Entertainment System.
A gun is also available to the player in Airflight for destroying enemies. Power-ups such as Super FC power boosters for guns, shields, and more are available to the player
For flipping gravity, there is a fireball ability.
The score, special weapons, and remaining lives are saved when a stage is completed.
They praised the "reverse gravity" gimmick as adding challenge and making the game unique, and said it was among the top 10 Hidden Gems for the NES emulator.