A Shoot 'Em Up series by Technosoft, which started with an obscure Japanese computer title in 1983 as a multi-direction overhead view shooter. It eventually become a side-scrolling shooter in the third installment, famous for its loads of Awesome Music.The Excuse Plot puts player in shoes of the GalaxyFederation's pilot in the Fire Leo starfighter against the overwhelming cybernetic ORN Empire. Thunder Force Vchanges the focus to Earth when Earthmen discover the wreck of Thunder Force IV's Fire Leo (Rynex) and reverse engineer it. The Guardian, an AI designed to study Vasteel (as Rynex comes to be known), however, goes haywire on humanity, but not before they create their own Vasteel starfighter. Thunder Force V is also known for having more story than the previous games, which ties together the events of IV. The sixth installment was trapped in Development Hell for a decade, but eventually released.The Thunder Force series spans six games:
Thunder Force (A variety of PC platforms, 1983) — The first game in the series, and the least well-known. Comprised entirely of overhead stages.
Thunder Force II (Sharp X68000, 1988) — Alternates between overhead sections and side-scrolling sections. Rereleased on the Genesis as Thunder Force II MD, with one less overhead-sidescroller pair and more balanced difficulty. MD itself was ported to Saturn via Thunder Force Gold Pack 1.
Thunder Force III (Genesis/MD, 1990) — Completely does away with overhead sections. Ported to the Saturn via Gold Pack 1.
Thunder Force AC (Arcade, 1990) — An arcade port of III (unusual in that ports generally go from arcade to console and not the other way around), but with altered 4th and 5th stages. Ported to the Saturn via Thunder Force Gold Pack 2, with an autofire feature that was not present in the original version.
Thunder Spirits (SNES, 1992) — A SNES port of AC (making it a port of a port), with a new stage 5 and stage 8. The least-known of the three versions of TFIII, despite being on the most popular platform of the three platforms it appeared on.
Thunder Force IV (Genesis/MD, 1992) — Released as Lightening (sic) Force: Quest for the Darkstar in North America. Ported to the Saturn via Gold Pack 2, with less slowdown and III's player ship as an unlockable ship.
Thunder Force V (Saturn, 1997) — The first game in the series with three-dimensional graphics, and introduces the Over Weapon system. Ported to the PlayStation as Thunder Force V: Perfect System, with less slowdown (but reduced visuals) and some omake content.
Thunder Force VI (PlayStation 2, 2008) — A whopping 11 years after the initial release of V and one failed attempt to bring it to the Dreamcast. Due to the low quality-to-anticipation ratio, it was not well received.
The Thunder Force series contains examples of:
A.I. Is a Crapshoot : Main plot of V. Humanity built a super computer named Guardian to study the wreckage of Rynex, the 4th game's Fire Leo. It then built a large fleet of starships based on the data. Then Guardian's AI damper program mysteriously disappeared and it turned against humanity with said fleet. Subverted. Guardian is still loyal to humanity. Chaos/Khaos (the Big Bad from the previous game) escaped its destruction by transferring its program to Rynex, which deleted the AI damper after Guardian accessed its history logs. In the end Guardian reveals that it helped humanity by purposefully spreading its forces thin and leaving critical flaws in its tactics, allowing the protagonist, Cenes Crawford to destroy the fleet.
Always Accurate Attack: The Free Range in V worked like this- anything entering the green wireframe area would be in for a world of (unavoidable) hurt.
Big Bad: Chaos/Khaos is pretty impressive one. After harassing The Federation for two games, we've finally blown it up in the third. Only to find it program was transferred to secondary system in the forth. And even reveal to be the one behind Guardian's rampage in fifth.
Bittersweet Ending: Thunder Force IV has the Rynex being crippled in the escape from the explosion following the defeat of Khaos and being abandoned to drift in space, while the scientists of the Galactic Federation admit that sending it in the first place was a mistake in the first place. It also hints at another threat named "Faust" is on its way. Yet they still have hope for humanity's future.
V has Cenes Crawford, pilot of the Gauntlet/Vambrace learn that the Guardian was on Earth's side all along, and that it did what it could to help her fight Khaos who was behind the corruption. Cenes destroys herself and the Vambrace so that another incident like that can not happen again.
Boring, but Practical: Twin Shot and Back Fire, the only weapons you don't lose when you die.
Boss Dissonance: Many bosses in III die within seconds of exposure to your weapons, especially the Sever. In contrast, the stages themselves have many deathtraps that demand twitch reflexes and R-Type-style memorization.
Evil Counterpart : The Vasteel Original (the Rynex) in V and Vasteel Nocht in VI.
Fallen Hero: The player's ship in IV, "Rynex", comes back in V as a Sequential Boss that you have to fight against and destroy.
Fan Sequel: Broken Thunder, released after V and before VI. The good news: Hyakutaro Tsukumo worked on the soundtrack. The bad news: It was so ill-received that it is theorized that Tsukumo's involvement with it was why he was left out of Thunder Force VI's soundtrack.
Fetus Terrible: The ORN Emperor in VI is an extremely ugly and monstrous infant with 3 eyes and varying number of irises in each of them. Apparently, the design was lifted from a character from a manga the project director had once drawn.
Final Boss Preview: IV had ORN Faust at the end of the Battleship Raid level. Your team of ships try to destroy it and get their asses completely handed to them, forcing the remaining members of your squad to resort in giving you the Mid-Season Upgrade. Thankfully, you get your revenge in the final level.
For Massive Damage: Many of the bosses in the series requires you hitting a weakpoint
Genre Shift: Across two games; Thunder Force II adds some side-scrolling areas to go with TF1-style overhead areas, and Thunder Force III does away with overhead areas completely.
Gratuitous Foreign Language: Two in Thunder Force VI—an obscure and obsolete offshoot of Chinese called Tangut, and Mongolian.
I Let You Win: The Guardian in Thunder Force V. Cenes Crawford in her last message even lampshades this by stating that had it not done so, the odds of just surviving those battles wasn't even in single digits.
It's Up to You : ORN's forces are so much greater than the Galaxy Federation's that if the Fire Leo fails, their regular forces won't stand a chance.
Subverted in IV where other Galactic Federation fighters team up with you to take on the Cerberus battleship before the trope gets played straight in the boss fight immediately following and for the rest of the game.
Subverted in V in that your character leads a squad of RVR-01 Gauntlets (named "Thunder Force", incidentally). Played straight later on as only the protagonistsurvives the battle at Babel.
Justified Extra Lives : Thunder Force V explained it as a cloning system called "Circulate Death"
Occurs again in VI. If player chooses the Phoenix fighter, it will become the Syrinx in last stage. For Brigandine, it only appear in intro movie.
Also happens in IV where the Rynex starts off functionally similar to the Styx, but at the halfway point it gets fitted with the Thunder Sword and gains spherical CLAW drones that serve as capacitors for the Thunder Sword.
Multiple Endings: IV just changes what song plays during the ending depending on the difficulty, but V's ending is decided by whether you beat the final boss fast enough, and VI has three endings depending on what ship and difficulty you chose and whether you used a continue.
Nintendo Hard: Thunder Force II. Especially the X68000 version.
Player Mooks: You can unlock the Rynex-R, the main fighter of the Galactic Federation, in VI
Precision F-Strike: In Thunder Force II, when you lose your last life, the robo-voice exclaims "Shit!".
Raising the Steaks: Iron Maiden from V is an undead animal of sorts (complete with flies, rotting flesh and blood). Its description? "It was dead, but alive at the same time".
Robo Speak: Any time you collect a weapon power-up.
Roboteching: The Hunter weapon. Your ship shoots out blue energy balls of doom that home in on the enemies.
Sequel First: The series didn't start getting released outside Japan until II
Sequential Boss: Many of them. Of note is Armed Armament Arm from V, who has three different forms. Same applies to UNKNOWN II, the Final Boss.
Single-Biome Planet : The sole exception is V which occurs on Earth. The ocean planet in VI is justified, it's post-global warming world and you will get pass the submerged city at one point. The jungle is really an abandoned space colony, with overgrowth forest took over residental area.
Space Zone: VI plays with this by having the background move around with no effect on gameplay at times.
Surprisingly Good English: All the English in V was there in the Japanese version as well. It kinda explains why the Guardian sounds slightly "off" compared to a native speaker.
Theme Naming: The ship names: Styx, Rynex, Syrinx as well as the Gauntlet, Vambrace and Brigandine