The story takes place in 2998, where humankind has reached a great point in intergalactic travel and space colonization with the help of a peaceful society, however a mysterious space matter known as Black Nebula appeared and begins engulfing different stars before reaching latest colonized galaxy by humans.
It is eventually revealed that the force behind this matter is Super Mech, a mysterious robot dictator from the farthest regions of space with the only intention to destroy any resistance that it and its massive space armada faces.
A Space Federation member, Captain Lancer, decides to initiate a surprise attack against Super Mech by piloting the only available space fighter craft, the CNCS1, loaded with Hellfire, the strongest weapon available in the galaxy.
In the Genesis version, Lancer returns safely to Earth after having defeated the Black Nebula
Hellfire is a science fiction-themed horizontally scrolling shoot ’em up game, where players assume the role of Captain Lancer taking control of the CNCS1 space fighter craft through six increasingly difficult levels, each with a boss at the end that must be fought before progressing any further, in a surprise attack effort to overthrow Super Mech, his army and the Black Nebula space matter as the main objective.
As far as horizontal scrolling shooters go, the title initially appears to be very standard, as players control their craft over a constantly scrolling background and the scenery never stops moving until the stage boss is reached.
A unique gameplay feature is the weapon system; players are equipped with four main weapons at the beginning that can be upgraded by picking up “P” icons and switch between them by pressing the change button, with each one shooting at a fixed direction no matter which way players move.
Other items can also be picked up along the way such as speed increasers and “B” icons that grants a number of points, which are crucial for reaching high-scores to obtain extra lives.
The Genesis version introduces the titular main weapon as an bomb capable of obliterating any enemy caught within its blast radius, as well as a shield and a satellite “option”.
Depending on the settings in the arcade version, the title uses either a checkpoint system in which a downed single player will start off at the beginning of the checkpoint they managed to reach before dying, or a respawn system where their ship immediately starts at the location they died at.
Getting hit by enemy fire or colliding against solid stage obstacles will result in losing a life, as well as a penalty of decreasing the ship’s firepower and speed to his original state and once all lives are lost, the game is over unless the players insert more credits into the arcade machine to continue playing.
Although there is an ending, the game loops back to the first stage after completing the last stage as with previous titles from Toaplan, with each one increasing the difficulty and enemies fire denser bullet patterns.