Gate of Thunder is a science fiction-themed scrolling shoot 'em up game, in which the player takes control of the Hunting Dog space fighter craft piloted by the space cop Hawk who, alongside his ally Esty piloting the Wild Cat support ship, must stop General Don Jingi and his Obellon armada from obtaining a powerful energy source known as "Starlight" from planet Aries.^[1][2] Prior to starting, a configuration menu can be accessed at the game's title screen, where any of the four available difficulty settings can be selected.^[1] The player controls Hunting Dog through seven increasingly difficult stages over a constantly scrolling background, populated with an assortment of military enemy forces and obstacles, and the scenery never stops moving until a boss is reached, which must be fought in order to progress further.^[1][2]

The weapon system is reminiscent of Thunder Force III;^[3] There are three types of weapon units in the game Hunting Dog can acquire by collecting their respective colors when the Wild Cat deploys them and alternate between each one at any given time during gameplay, ranging from laser (blue), waves (green) and earthquake (red).^[1][2] Collecting any weapon unit also equips Hunting Dog with a set of two satellite-like options that blocks incoming enemy shots, as well as firing forward or backwards by double tapping the fire button.^[1][2] Each weapon can be powered-up once and when all weapons are maxed out, collecting an additional weapon unit unleashes a firewall capable of obliterating enemies and bullets caught within its range.^[1] Wild Cat will also deploy supplementary units such as homing missiles and a three-hit force shield.^[1][2]

Hunting Dog is also equipped with a speed setting, which can be increased or decreased across three levels by pressing the select button.^[1] Firing on determined locations of a stage will reveal a secret item within its scenery. The title employs 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 live, as well as the weapon that was currently in use by Hunting Dog, and the game is over once all lives are lost, though the player has limited continues to keep playing.^[1]