Seven Force is the boss of the Underground Mine stage from Gunstar Heroes. It's a machine piloted by Green that can transform into seven unique forms. Players on normal difficulty only have to fight five forms, but on expert they must fight all seven. Each transformation has different moves, vitality, and patterns.
The Seven Force fight always starts with Soldier Force. The other forms that follow are random. Soldier takes on a humanoid shape that gives chase down a horizontal shaft. Its primary attack involves shooting its arm like a missile. It can also throw exploding spheres or blades that fly like boomerangs. On harder difficulties it uses a slide attack if players stay on the ground for too long.
Tails is fought in a vertical shaft. It has a long tail with a spinning spiked ball on the end and flies around the edges of the screen. Occasionally it will get in close and do a number of flips. It also has a machine that it can use while floating in the center of the screen, or while it moves around the edges of the shaft.
Tiger is a four legged form fought in a horizontal shaft. It runs along the bottom of the screen and uses its tail to fire lasers and explosive shots. If the player is too close, it can also do quick flips and pounces. Its laser attack is designated by an outline of the beam before it fires. The explosive shots are designated by cross hairs that move along the top of the screen. The cross hair can expand signifying a larger explosion.
Urchin is a pinwheel form that is fought in a vertical shaft. Early on, it rolls around the top and bottom of the screen before quickly moving up or down a wall to the other side. After it takes enough damage, it will relocate to the center of the screen and fire off energy balls in random patterns until it is defeated.
This form is in the shape of a crab and is fought in a horizontal shaft. It moves away from the player while dropping exploding mines and expanding walls to create a deadly obstacle course. The speed and combination of obstacles it drops depends on what difficulty the game is set on.
Eagle takes the shape of a bird and is fought in a vertical shaft. Its primary attack is making passes up and down the shaft while dancing back and forth. It only leaves a small opening for players to sneak by without getting hit. Eagle's dance attack on normal is slow, while on expert it will move faster. It can also fire lasers if the battle goes on too long.
Blaster is in the shape of a giant pistol. It spins around in a stationary position while taking shots at the player. After a number of rounds, it will take a break to reload complete with an animation for switching out magazines. This form of Seven Force can be exploited so the player can avoid all damage. There's a spot under the "trigger" where Blaster is unable to hit the player.
In Gunstar Super Heroes for the GBA, Blaster Force is replaced with Archer Force. Instead of a gun, it takes the shape of a bow and arrow and has no blind spot.
Seven Force - The Final Assault
Seven Force makes one last appearance as a boss of a stage in space. It appears much smaller only because the player is flying a space ship. For this battle it changes freely between all seven forms to use different attacks. Soldier uses a triple shot. Tails flips across the screen. Tiger becomes a dash attack. Urchin fires lasers in 360 degrees. Crab drops mines. Eagle chases the player while firing lasers. And Blaster fires shots that explode into smaller projectiles.
A variation of Seven Force appears in Alien Soldier for the Sega Genesis under the name 7th Force. Stage 20 features a boss fight against a woman who can turn into a number of different creatures. The fight uses a variation of the music in Gunstar Heroes for Seven Force and every form shares the "Force" naming convention. However, there are only six forms including the woman's human form. And instead of shapes, forms are named after mythological beings.
Each force is introduced by the woman with a voice clip.
Valkyrie takes on a humanoid shape attacking with kicks and punches. It has two projectile attacks in the form of firing its fist like a missile and (as a nod to Soldier Force) throwing a giant boomerang weapon.
Valkyrie's weak point is the sphere located in its upper body.
Medusa has a wheel-like form similar to Urchin Force. It tries to run over the player while rolling through a narrow passageway. At certain points it will unfold and whip around it with four tentacles.
Medusa doesn't have a specific weak point and it can be shot anywhere to cause damage.
The fight against Sylpheed takes place in a free fall similar to Eagle Force. It floats back and forth and takes wide swings with its large arms. Attempting to shoot it will cause it to block its head with its two arms.
Slypheed's weak point is its head.
Artemis is a cat-like shape that is fought on the ground similar to Tiger Force. Its primary attack is jumping around to cause collision damage, but it can also do a back flip and launch an explosive shot from its tail.
Artemis' weak point is its tail.
Sirene Force is the last form and is fought under water. It floats back and forth in a steady circle while dropping mines and swinging its flails (similar to Tails Force's tail) around the screen.
Sirene's weak point is the sphere in its main body. Defeating Sirene will end the fight with 7th Force.
Gunstar Super Heroes
Seven Force's most recent appearance is in Gunstar Super Heroes . It appears as the boss of the second moon. A cut scene before starting the level refers to Seven Force as an old relic dug up by the Empire that was quickly put to use as a weapon. All but one of its forms are taken from Gunstar Heroes and given an updated, more rounded shape compared to the blocky design of its first appearance.
A number of changes have been made to Soldier in Super Gunstar Heroes. It is no longer the very first form players fight and has been given several new attacks. It can fire lasers in a fan pattern, fly through the air to drop bombs, kick a giant sphere as a projectile, launch its arms to fly around in a circular pattern, and throw a boomerang.
Tails is still fought in a vertical shaft and has many of the same moves from Gunstar Heroes. Besides using a rapid fire weapon and swinging its tail around the screen, it can also launch rockets that travel up the left side of the shaft in an alternating pattern.
The fight against Tiger Force has been altered to be much less predictable. It no longer uses attacks with visible cross hairs or outlines of laser patterns. Instead it fires lasers directly in front of it and launches tiny exploding blue spheres. Players can no longer stay on the ceiling as it can now use a somersaulting attack that reaches the top of the shaft.
Urchin still relies on rolling up and down the shaft to try and run over the player, but it can also drop lots of tiny bombs in the process.
Crab is nearly unchanged from Gunstar Heroes. It drops expanding walls, mines, and an explosive sphere. Players that get too close can be shot by a machine gun that fires out of the center of Crab.
Eagle's attacks have been completely changed in Gunstar Super Heroes. It no longer moves up and down the shaft. Instead it takes position at the top of the screen to bomb the player with energy spears and fire. It also creates hoops of blue flame that players have to jump through in order to avoid taking damage.
Archer replaces Blaster Force from Gunstar Heroes. It takes the shape of a bow and arrow and fires giant arrows. It can fire one, two, or three in a spread pattern. Occasionally it will launch an exploding sphere.
Seven Force - Final Battle
The last stage of Gunstar Super Heroes brings Seven Force back one last time. During a fight with Green, he can change into any of the forms at will to use different attacks. Soldier uses a hard kick, Tails spins across the screen, Tiger does back flips, Urchin rolls across the ground, Crab drops bombs from the top of the screen, Eagle fires a wave of lasers, and Archer fires several arrows.