Blaster Master, known in Japan as Super Planetary War Chronicle: Metafight or simply Metafight, is a 1988 platform/run and gun video game developed and published by Sunsoft for the Nintendo Entertainment System. The game is the first in the Blaster Master series, and spawned two spin-off games as well as two sequels. The game follows Jason as he discovers a tank known as Sophia the 3rd, which he uses to battle radioactive mutants. The player controls Jason and the tank through eight levels of gameplay in order to find the whereabouts of Jason's pet frog Fred, and to defeat the mutants and their leader, the Plutonium Boss.

Blaster Master was praised for its smooth play control, level designs, detailed and clean graphics, and music, but was criticized for its high difficulty level and lack of passwords or save points. The game was novelized by Peter Lerangis as part of the Worlds of Power series by Scholastic Books.

In the Japanese version of the game, the plot is only explained in the manual. The game takes place on the planet Sophia the 3rd, located near the center of the Epsilon Galaxy, in which an advanced civilization flourished. In the year 2052 of the space age calendar, the Invem Dark Star Army, led by the universe's most feared tyrant Goez, invade and conquer Sophia the 3rd. The Science Academy of NORA, a satellite orbiting near Sophia the 3rd that somehow managed to avoid the invasion, built a weapon, an all-purpose tank called the "Metal Attacker", in a last-ditch effort to defeat Goez's army. A young soldier named Kane Gardner is chosen as the pilot of this weapon. The game's opening sequence shows Metal Attacker being dropped into the battlefield.

The plot of the adapted Western release (Blaster Master) is shown at the beginning in a cinematic slideshow as ominous music plays in the background. The game starts with a person named Jason who has a pet frog named Fred who, one day, decides to leap out of his fish bowl, out the door, and down a hole in the back yard. Fred then touches a radioactive chest, and he grows to an enormous size; Fred and the chest then fall deeper into the hole in the earth. Jason chases Fred down the hole, which leads to a large cavern. While most sources say that Jason chased Fred down the hole, the game's instruction manual says that Jason fell into the hole while trying to reach for Fred. There, he finds an armored tank named SOPHIA THE 3RD – a vehicle designed to battle radioactive mutants that live inside the Earth. Jason mounts SOPHIA to find the whereabouts of Fred and to destroy the mutants and their leader – the Plutonium Boss.

Blaster Master has two modes of gameplay that depend on the situation and location of the player: the first mode is where the player controls Jason; either on foot or piloting a tank named SOPHIA in a two–dimensional platform mode; the second mode is where the player controls Jason on foot in a top-down perspective. Gameplay in the top-down perspective consists of a series of labyrinths in which players navigate and defeat enemies along the way. Gameplay is non-linear, and players must return to earlier levels in order to advance to later levels in the game. The objective is to complete all eight levels and destroy the mutants and their bosses with various weaponry such as guns, grenades, and special weapons.

While Jason is inside SOPHIA in the 2D platforming mode, the player can attack the mutants with the main cannon (which can shoot up, left, and right determined by the orientation of the tank) or with one of three special weapons. Special weapons have limited ammunition which must be collected from exploring the game. They include the following: homing missiles that, when fired, shoot 1 missile at each enemy on screen up to 4; "Thunder Break", which fires a high-damage lightning bolt downward; and "Multi Warhead Missiles", which simultaneously fires a set of three missiles at enemies in front of and diagonally up and down. Players select their special weapon and monitor the amounts of each special weapon left by accessing the Menu Screen by pressing the Start button.

The player switches between the 2D platforming mode and the top-down perspective by leaving the tank and entering small doorways located throughout the game. While in the top-down perspective, players can move Jason in any direction and destroy mutants with a gun or with hand grenades. In this mode, players upgrade the gun by collecting gun capsules, but the gun degrades by one point if Jason receives damage from mutants or hazardous objects. Here players obtain additional vehicle functions by destroying bosses; these functions include weapon upgrades as well as abilities to swim freely underwater, drive on walls and ceilings, and hover above the ground. The game has a glitch – colloquially known as the "grenade glitch" – to easily defeat four of the game's underbosses. To exploit this glitch, the player throws a grenade at the boss, and while the grenade is exploding and causing damage on the boss, the player pauses the game. While the remainder of the action on the screen freezes, the grenade remains active, continuing to damage the boss. After fifteen seconds the player unpauses the game to find that the boss is destroyed.

Jason and SOPHIA have separate power meters, and they decrease whenever they sustain damage by an enemy or any other hazardous object or whenever Jason falls from a high place. Players can replenish these power meters by collecting power capsules that appear throughout the game. Also, the player can replenish Jason's health to full at any time by re-entering SOPHIA. The player loses a life if either power meter runs out, and the game ends when all lives are lost. Players get four continues that allow them to restart the game at the same level in which they have lost all their lives. A "hover gauge" monitors the amount of thrust remaining in SOPHIA and is located on the left side of the screen above the power meter; additional thrust can be obtained by collecting hover capsules.