Humanity has advanced technologically enough to begin expanding to space colonies. However, in space history X085, the 16th colony ORBIT declares independence and launches an attack on the Earth. In response, the Earth government establishes the Space Defense Force ALTAIR and repels ORBIT's attack. Despite the successful defense, tensions between ORBIT and the Earth remained, and in space history X122, ORBIT launches another attack on the Earth.
The player takes on the rule of a pilot in command of STRAHL, a cutting-edge space fighter, with veteran Ace Pilot Master Takahashi (yes, played by and voiced by himself) serving as commander.
The game plays similar to 16-bit shooters, with heavy inspiration from Star Soldier in particular, complete with a five-way shot that fires straight ahead and in the four diagonal directions. This game's main gimmick is the "special shot" feature. Holding down the fire button releases a "normal" continuous-fire shot that is fine for cannon-fodder one-HP Mooks, but may have difficulty taking down more durable enemies. By instead tapping the fire button repeatedly, the player's ship will fire a more powerful type of shot, with the bullets becoming stronger the faster the player presses the fire button (up to a certain point). However, the special shot runs on a gauge and will be unusable if the gauge runs out; the gauge can be replenished slowly by not firing or only using the normal shot, or instantly refilled by collecting a yellow "SP" item.
There are four game modes: Arcade is a conventional 7-stage campaign, Caravan is a 2-minute dedicated score attack stage, Challenge tests the player's abilities in a series of trials, and Rapid Fire challenges the player to tap the shot button as many times as possible over the course of ten seconds and can be played single-player or with up to three other CPU or human opponents.
See also Raging Blasters, an earlier game by Terarin that was also inspired by Star Soldier.
Star Gagnant provides examples of the following:
- As Himself: The player's commander, Master Takahashi, is played by Takahashi Meijinnote himself.
- Breaking Old Trends: Due to being a collaboration with Takahashi Meijin, there are some staples from past Terarin games that are different or missing:
- This is the first Terarin game not to feature the point crystals that are released when destroying an enemy. Missile Dancer 2 would then follow suit.
- Caravan modes in past Terarin titles were 3 minutes long, but in this game, it's only 2 minutes long.
- Not only is this the first Terarin work to be released on Switch first, it's only available on Switch, As a result, it's also the only Terarin game not to be available on Windows PC.
- This is the first Terarin game to have four difficulty levels instead of three.
- Button Mashing:
- Holding down the fire button shoots a normal shot that does a faint amount of damage. To inflict better damage, particularly against armored enemies, the player needs to rapidly tap the fire button to use their special shot.
- Rapid Fire is a minigame where you try to mash the fire button as fast as possible over the course of 10 seconds.
- Excuse Plot: The background story isn't particularly deep and is just an excuse to have the player blow up enemies while under the duty of the guy who can tap "fire" 16 times a second.
- Gameplay and Story Segregation: Stage 5 is a "Fire Planet" where your superiors advise you against staying on the planet for too long lest it start to damage your ship. However, this never comes into play gameplay-wise, and while the two bosses of the stage do have time limits, timing those bosses out only results in the usual scoring penalties (no points for destroying the boss and no time bonus) as the boss self-destructs, allowing you to carry on as usual.
- Genre Throwback: Like Terarin's previous shmups, this 2023 game is a throwback to shmups of the late 80s and early 90s, in contrast to modern Bullet Hell shooters of the 2010s and 2020s.
- Harder Than Hard: After completing Arcade mode on Hard difficulty, the player unlocks Meijin difficulty, named after Takahashi Meijin himself.
- Invincibility Power-Up: Leveling up your shot or collecting a shield item will give you a brief period of invincibility.
- Law of Chromatic Superiority: Your shot color advances up the color hue spectrum the more powerful it is: Normal shots are red, and then special shots are colored, in order from least to most powerful: yellow, green, and blue.
- Lethal Lava Land: Stage 5 is set on a "Fire Planet" where erupting fireballs and prominences can damage the player's ship. In-story, the player is advised to avoid staying on the planet too long lest it melt their ship, however the only semblance of time pressure are the usual boss time limits.
- Musical Pastiche: The Caravan mode theme is loosely based on, but not quite a remix of, the History 1 theme from Starship Hector, which was also used in Super Star Soldier's 2-minute Caravan stage.
- No Fair Cheating: If the game detects a press rate of more than 16 Hz, the game will assume you're using an autofire controller and immediately drain out the special shot meter. If you have a controller that can autofire at less than 16 Hz (which are rather rare, as many controllers with autofire use a fixed 30 Hz), this can be circumvented. From version 1.0.2 onward, even if you use an autofire of less than 16 Hz, the game will stil detect it and show an "AUTO FIRE" text next to the Rapid Fire counter.
- Public Domain Character: Hera shows up as one of the midbosses of Stage 4. However, she is referred to as "Mirror Goddess Hera"; her original characterization has nothing to do with mirrors.
- Retraux: The game has the look and audio of a 16-bit game, more specifically PC Engine games. Can be taken a step further with the soundtrack's chiptune arrange and the graphics' retro arrange, making the game look and sound 8-bit.
- Single-Use Shield: The blue 'S' item grants the player's ship a shield that can withstand one hit. Having a shield is important because getting destroyed outright knocks your weapon level back to 1.
- Timed Mission: Caravan mode, which drops you into a dedicated stage and gives you two minutes to score as many points as possible. It's one of the game's many nods to the Star Soldier series, which are known for their Caravan stages.
- Time-Limit Boss: Every boss is on a time limit. Destroying the boss awards, in additon to the "Excellent!" for destroying it, 100 points for every second left if it's a midboss and 1,000 points for every second left if it's an end-of-stage boss. If the timer runs out, the boss self-destructs and you move on but you forfeit the "Excellent!" bonus and the time bonus.
- Warm-Up Boss: The stage 1 boss, Baby Unit, is a pushover that alternates between a slow spread pattern of Destructible Projectiles and a blatantly-telegraphed Wave-Motion Gun. Its second form shoots a spiral spread of bullets that is a bit more difficult but is still small time compared to what later bosses will throw at you. The challenge is in trying to destroy it as quickly as possible to get a good time bonus, a priority that will take backseat with later bosses whose attacks will pose more of a threat.
- You Are Too Late: In stage 7, after defeating Villan, he brags that you're too late to stop the Master Core from obliterating the Earth. You then have to destroy the Master Core to truly stop his scheme.
