Journey to Silius was originally conceived as a game based on the 1984 film The Terminator. To protect the colony plans and to avenge his father's death, Jay sets out to fight the terrorists responsible for the space colony's destruction. In his father's home, Jay discovers a floppy disk containing not only the complete SSS colony plans but a personal message from his father asking that he complete the projects should terrorists succeed in destroying the colony. However, the space station is obliterated in an explosion, killing the entire research team and destroying all data on board. Jay McCray, the son of a scientist responsible for development of space colony #428 in the Silius Solar System (SSS), prepares to move there in order to follow in his father's footsteps. In the year 373 of the new space age calendar, overpopulation of Earth has led to increased demand for emigration to space colonies. After the fifth and final stage is completed, the credits are shown, and the player would restart the game on the first stage. The player can replenish Jay's health and ammo by retrieving energy capsules dropped by defeated enemies.
Each of these special weapons consumes the player's Gun Energy gauge and once it runs out, the player would automatically revert to the default handgun. In addition to the default handgun weapon, the player can switch to one of five additional weapons that can be procured throughout the course of the game - which are a shotgun, a machine gun, a homing gun, a laser rifle, and a grenade launcher. The character can lie down, but he can only aim his gun left or right. The controls follow the standard conventions of other side-scrolling action games for the NES. The player must fight his way through an assortment of robotic enemies and security systems in order to reach the end of each stage and fight the stage's boss. There are five stages, consisting of the ruins of a space colony, an underground concourse, the enemy's hideout, a flying spaceship, and a factory. The player controls Jay McCray, as he goes on a mission to defeat the terrorist group responsible for his father's death.
Jay encounters the first enemy in the first stage of Journey to Silius.