Last updated
Gradius logo.svg
Genre(s) Scrolling shooter
Developer(s) Konami
Publisher(s) Konami
Platform(s) Amiga, Amstrad CPC, Arcade, Commodore 64, Game Boy, Game Boy Advance, Microsoft Windows, mobile phone, MSX, NEC PC-8801, Nintendo 3DS, Nintendo DS, Nintendo Entertainment System, Nintendo Switch, PC, PC Engine, PlayStation, PlayStation 2, PlayStation Network, PlayStation Portable, PlayStation Vita, Super NES, Tomy Tutor, Vectrex, Wii (Virtual Console), Wii U, WiiWare, X1, X68000, ZX Spectrum
First release Gradius
February 2, 1985
Latest releaseGradius the Slot
July 2011
Spin-offs Salamander

Gradius (グラディウス, Guradiusu, /ˈɡræd.i.əs/ GRAD-ee-əss) is a series of shooter video games, introduced in 1985, developed and published by Konami for a variety of portable, console and arcade platforms. In many games in the series, the player controls a ship known as the Vic Viper.



Release timeline
1981 Scramble
1985 Gradius / Nemesis
1986 Salamander / Life Force
1987 Nemesis 2 (MSX)
1988 Gradius II
Nemesis 3: The Eve of Destruction (MSX)
1989 Gradius III
1990 Nemesis (Game Boy)
1991 Gradius: The Interstellar Assault / Nemesis II
1996 Salamander 2
1997 Gradius Gaiden
Solar Assault
1999 Gradius IV
2001 Gradius Advance
2004 Gradius V
Gradius NEO
2006Gradius Collection
2008 Gradius ReBirth
2010Gradius ARC
2011Gradius the Slot

An early horizontal-scrolling shooter from which gameplay elements of the Gradius series were inspired. Although there is no canonical relationship between Scramble and the Gradius series, Scramble is implied to be a spiritual predecessor to the series, evident by its appearance in flashbacks during Gradius introduction sequences. ( Gradius Advance ) Scramble has been ported to other platforms; including MSX and Commodore 64. In 2002, Scramble appeared on GBA as one of the titles featured in Konami Collector's Series: Arcade Advanced as well as later Konami game compilations for PlayStation and Nintendo DS.

The first true Gradius game to introduce the concept of the 'weapon bar'. During the game, many enemy craft leave behind icons or 'pick ups' when destroyed. Collecting one of these will shift the selection cursor along the weapon bar at the bottom of the screen. The player can then select the weapon highlighted if they want it. The cursor then resets. In general, the more useful 'power ups' are towards the right hand side of the bar, so the player may decide to stock up on pickups until the better item is available. This innovation allowed for deeper tactics on the part of the player and for greater freedom of weapon choice rather than relying on the pre-determined power ups common in other games in the genre. Originally released as an arcade game, its popularity resulted in ports to the: ZX Spectrum, Commodore 64, NES/Famicom, MSX, Master System, Sharp X68000, Amstrad CPC and PC Engine. More recently, ports to the Sega Saturn, PlayStation, and certain mobile phones were created. (Saturn, PlayStation and computer versions are all packaged with Gradius II as Gradius Deluxe Pack). In addition, the NES version was re-released for Virtual Console, NES Classic Edition and the PC Engine version on the PlayStation Network. In territories outside Japan, the arcade and MSX versions of Gradius were released under the title Nemesis. [1] [2]

Set in the same continuity as Gradius. The game is noteworthy for a number of reasons. Most prominently, the game switches between horizontal and vertical stages, one of the first games of its kind and was also one of the first shoot'em ups to include cooperative gameplay.

The first player ship is Gradius's own Vic Viper ship, while the second ship is the Lord British space destroyer (sometimes called the "RoadBritish") which is based on the F-16 Fighting Falcon. Unlike Gradius, Salamander uses a more conventional weapons system, with enemies leaving a wide variety of distinct power-ups. The NES version of Salamander, called Life Force in North America (and marketed in that region as the "sequel" to the first Gradius), and the MSX version used the power meter from the Gradius series. There also exists an arcade game named Life Force that is identical to Salamander released in Japanese arcades the same year, except that a Gradius-style power meter is used instead of conventional power-up items, and the stages were recolored slightly and given some voiceovers to make the mission about traveling inside someone's body, rather than through space; stages took on names such as "Kidney Zone" and "Stomach." An American release was also made, but it retained the original power-up system of Salamander, though it was renamed as Life Force.

The MSX Gradius 2 is unrelated to the second arcade Gradius game (which used the Roman numeral "II"). Instead of controlling Vic Viper, the available ship is called "Metalion" (code name N322). Like the MSX version of Salamander, this game also has a storyline, which is told by cutscenes. The gameplay is mostly unchanged from the rest of the series, though there are some power-ups that temporarily give the ship some enhancements. In addition, when the bosses are defeated, the Metalion can fly inside them before they explode, and a mini-level will start that awards weapon upgrades when finished without dying, depending on the speed at which the boss was defeated. In the same year Zemina released a version for the Korean Master System. This version was ported to the Sharp X68000 computer under the name Nemesis '90 Kai, with a number of graphical and aural enhancements. A graphically enhanced version with smooth scrolling appeared in the Japan exclusive PSP Salamander Portable collection.

Bearing no relation to the MSX game titled Gradius 2, Gradius II is the sequel to Gradius in terms of chronology. The game did not see a North American release until 2006 as part of the PlayStation Portable title Gradius Collection . On November 12, 2020 it was released on the Nintendo Switch as part of Hamster's Arcade Archives series. It was released as Vulcan Venture in territories outside Japan. [3]

The fourth game of the series to be released for the MSX platform. "Gofer no Yabō" (GOFERの野望) is coincidentally also the subtitle of Gradius II for arcade. Like the other MSX titles in the series, Nemesis 3 has an over-arcing plot depicted through the use of narrative cut-scenes. Nemesis 3 retains Gradius 2's weapon capture system, although weapons are obtained by navigating the player's ship into secret alcoves scattered throughout stages rather than entering enemy core ships. The game additionally allows the player to select a preset weapon configuration before starting.

This title introduced the Weapon Edit method of selecting weapons, which allowed players to create their own weapon array by choosing power-ups from a limited pool of available weapon types (some weapons in the preset weapon types are not selectable in Weapon Edit mode, although it includes weapons not in any presets). The SNES/SFC version is not a very accurate port; levels, enemies, and weapons were altered. For example, two entire stages were cut out in the Super NES version: a 3D stage which involved avoiding hitting cave walls from a unique first-person perspective behind the Vic Viper, and a crystal stage in which the Vic Viper was challenged by crystal blocks blocking off areas like a maze. Also, the order of stages was changed. The final stage in the SNES version was based on an early stage in the arcade version. The original arcade version's ending had the main boss in a mechanical setting, then going through a speed-up zone to escape the enemy base, whereas the SNES version had the player simply avoiding the final enemy's simple and slow-moving attack patterns with no challenge afterward. However, the SNES version introduced the Rotate and Formation Option types, both of which were reused in Gradius V. The difficulty and major boss tactics were toned down to make it easier. The original arcade version is available for PlayStation 2 bundled with Gradius IV (Gradius III and IV), although the port has some slight differences from the original.

Only released in Japan, rather than a video game this spin-off game is a token gambling game with a Gradius theme.

The first Gradius for a portable system, in this case Nintendo's Game Boy. The name Nemesis was kept for the game's worldwide release, as the game retains some of the elements that were otherwise exclusive to the MSX titles, such as hidden bonus stages. It was later ported with full color support as one of the four games in the Konami GB Collection Vol. 1 for Game Boy Color entitled "Gradius".

Another Gradius game exclusively for the Game Boy. It was one of the larger Game Boy carts in existence at the time (2-Megabits), and was completely different from the rest of the series—most of them used music, enemies, bosses and even levels from previous games in the series, but this one did not, except for the boss music from the first Gradius game with the addition of a small original part to the piece. A little bit of the "between levels" music from Gradius III can also be found at the very first part of the game. It was released as Nemesis II in Japan and as Nemesis II: Return of the Hero in Europe.

The follow-up to Salamander. It had several unique features, such as the Option Shot, the ability to launch the Options as homing projectiles. After firing, an Option would revert to a smaller, less powerful unit called an Option Seed, which revolves around the ship firing the default shot. Weaponry includes Twin Laser, Ripple Laser, and standard Laser. Like its predecessor, Salamander 2 uses a conventional power-up system, rather than the Gradius power meter. Upon acquiring a second power-up of the same type, the player's weapons are twice as powerful for a short duration (10 seconds). The game features variations of previous Salamander bosses, such as the Golem and Tetran.

The first Gradius produced exclusively for a home console. This is also the only Gradius game (other than Gofer no Yabō Episode II on the MSX) where players can select which ship they wish to use. Gradius Gaiden includes the Lord British Space Destroyer from Salamander and two (relative) newcomers: the Jade Knight and the Falchion β (a variation of the ship from the Famicom Disk System game Falsion). It was originally released for the PlayStation console and ported in 2006 as part of Gradius Collection for the PlayStation Portable. In 2019, it was included in the Japanese version of the PlayStation Classic mini console.

Solar Assault is an arcade 3D rail shooter in the lines of Star Fox or Panzer Dragoon , with Gradius's settings. As usual, Vic Viper makes an appearance here, with two other ship choices available: Lord British and Alpina. This game was very obscure and was never ported to any console system.

Released in Japanese arcades as Gradius IV Fukkatsu ("fukkatsu" (復活) being Japanese for "revival", since it was the first arcade Gradius game in 10 years, following 1989's Gradius III). IV lacked the Weapon Edit function of its predecessor, but it had a bigger array of weaponry than the original Gradius games. Weapons exclusive to this game included the Vertical Mine missile (which detonates in a vertical line shortly after deployment) and the Armor Piercing laser (a shorter-ranged, more powerful laser). It was released on the PS2 in a compilation pack together with the arcade version of Gradius III (Gradius III and IV).

The first Gradius to be created by a development team other than Konami's own internal teams (by Mobile21, to be exact). A Game Boy Advance title, it is known as Gradius Galaxies in USA and as Gradius Generation in Japan. The Japanese version, being the last to be released, has a number of exclusive challenge modes added and includes an additional invisible 5000 point bonus in one of the levels.

Gradius V was released in September 2004 for the PlayStation 2. Graphics are rendered in full 3D, although gameplay is still mostly 2D; some areas change the position and perspective of the camera to emphasize the 3D environment. Treasure (developers of Gunstar Heroes , Guardian Heroes , Radiant Silvergun and Ikaruga , among others) were primarily responsible for Gradius Vs development. In the Japanese first-press limited edition, the game included a book detailing internal design, background, and a road map of the Vic Viper series (i.e., "Vic Viper" is the name of a ship series, rather than a single ship), and pre-ordered North American copies included a DVD detailing the history of the series (including Scramble) and replays of Gradius V.

Released only to mobile phones, it features another storyline, taking place roughly 2000 years after the last Nemesis. It is also the first game to give players the ability to control their "Multiples" in formations, with formations variable depends on buttons.

A Gradius compilation for PlayStation Portable. This compilation contains the classic versions of Gradius I-IV with a few bonus features thrown in as well as the first international release of Gradius Gaiden.

A Gradius title for WiiWare. It draws most of its elements from the MSX games rather than mainstay Gradius staples. The game's plot sets the stage for the events depicted in Gradius 2 (MSX).

In March 2010, a Japanese trademark database update revealed a filing for this name, submitted by Konami. [4] The "Arc" portion of the name coincided with a pre-release name of the PlayStation Move. This was only a coincidence, however, as Gradius Arc —Ginyoku no Densetsu— (Gradius Arc —Legend of the Silvery Wings—) was revealed on September 30, 2010, to be a tactical RPG for cell phones. [5]

A pachislot game released in Japan in July 2011. [6] It was developed by the KPE division of Konami. A soundtrack for the game was released in September 2011.


The Parodius series, started in 1988, is similar to Gradius, but with more cartoony settings. The name is a portmanteau of "parody" and "Gradius". Many of the mainstays of the Gradius series are included, albeit in a parodied format; this includes neon-colored core warships, effeminate moai, and large dancing women as bosses. Early games focused mainly on parodying Gradius games, but more recent games have poked fun at other Konami franchises, including Castlevania and Ganbare Goemon . The games offer a large number of different characters to use, each with different weapons. The characters consist of ones created for the series, such as Takosuke, and popular Konami characters like Pentarou and Upa (from Bio Miracle Bokutte Upa ). Vic Viper also appears in all titles. The Parodius games also distinguish themselves from the Gradius series in their music. Unlike the Gradius games, whose music are either unique to each game or refer to earlier games in the series, the music in the Parodius games parodies a diverse pool of public domain sources, including a large contingent of classical music.

A platform game released on the Famicom starring an anthropomorphic moai statue.

A newer take from Konami on the Gradius spoof, this game features anime girl representations, designed by Mine Yoshizaki, of Vic Viper and Lord British, in a mecha musume-style approach. The name is a portmanteau of "otome" (乙女, a Japanese word meaning "maiden") and "Gradius."

Cancelled games

Common elements

There are several gameplay elements that are common to almost all the Gradius games. These include the power meter, one of the Gradius series' defining characteristics, is enabled by power-up items. The items upgrade the selected ability in the power meter. The meter resets when the player chooses to activate the selected ability. Weapon edit lets players create their own power meter sequence.

The concept of the "Core" is a central part of Gradius. Cores are usually blue, glowing masses of energy hidden within large warships and protected by a series of barriers. All cores must be targeted in order to defeat a warship, which normally comprises several phases and often uses the terrain to its advantage. In some cases, a core is closed or not vulnerable at the beginning of a battle, only opening or becoming susceptible to attack some moments later by turning blue. Additionally, the announcer will normally urge the player to "Destroy the core!" or "Shoot the core!" prior to an encounter. For other types of bosses, like large beasts, the announcer may command the player to "Destroy the eye!" or "Destroy the mouth!", depending on the boss.[ citation needed ]

The moai statues of Easter Island (Chile) appear as enemies in several Gradius games. They are mounted on either side of flat, free-floating platforms and fire a series of colorful rings at the Vic Viper. Upon completing the game, the player restarts on the first level while retaining their upgrades from the previous games. Each cycle through the game grows progressively more difficult. The Nintendo Entertainment System port of Gradius represents the first ever use of the Konami Code. [7] If the player pauses the game and enters the Konami Code (Up, Up, Down, Down, Left, Right, Left, Right, B, A), they will be given most of the power-ups except Laser, Double and Speed Up.[ citation needed ]


The Gradius series was created when Hiroyasu Machiguchi, the series creator was given a team to work with and asked everyone what kind of game they wanted to develop, to which they responded being a shoot 'em up, with the intent of surpassing Namco's Xevious . [8] They decided to make it a horizontal shooting game because they wanted to reuse material from Scramble as much as possible, and Gradius was originally named Scramble 2. [8] The development lasted for a year after refining and experimenting with the gameplay. The team originally tried twenty different movement patterns for the Options and used a process of elimination when something did not work. [8] For the story, Hiroyasu's team was inspired by science fiction movies, with the popular sci-fi films at the time being Star Wars and the anime adaptations of Lensman . The team saw Lensman together and it influenced the game's story. Its plasma laser also left a big impression on them and was why Gradius featured a Laser weapon. [8] The Moai were included because they wanted to add a mysterious element to the game like Xevious and its Nazca Lines.

Reception and legacy

Hideki Kamiya stated in an interview that Gradius is one of the top three key inspirational games from his past. [9]

Several of Gradius' starfighters, Core bosses, and various game elements have been adapted into trading cards as part of Konami's Yu-Gi-Oh! Trading Card Game.

In other media



Related Research Articles

<i>Gradius</i> (video game) Sidescrolling shooter video game by Konami

Gradius is a side-scrolling shooter video game developed and published by Konami. The first game in the Gradius series, it was originally released as a coin-operated arcade game in 1985. The player maneuvers a spacecraft known as the Vic Viper that must defend itself from the various alien enemies. The game uses a power-up system called the "power meter", based upon collecting capsules to purchase additional weapons.

<i>Salamander</i> (video game) 1986 video game

Salamander, retitled Life Force in North America and in the Japanese arcade re-release, is a scrolling shooter arcade video game by Konami. Released in 1986 as a spin-off of Gradius, Salamander introduced a simplified power-up system, two-player cooperative gameplay and both horizontally and vertically scrolling stages. Some of these later became normal for future Gradius games. In Japanese, the title is written using ateji, which are kanji used for spelling foreign words that has been supplanted in everyday use by katakana. Contra, another game by Konami was also given this treatment, with its title written in Japanese as 魂斗羅.

<i>Jikkyō Oshaberi Parodius</i> 1995 video game

Jikkyō Oshaberi Parodius is the fourth game in the Parodius franchise, a series of parody shooters produced by Konami. The gameplay is stylistically very similar to the Gradius series, but the graphics and music are intentionally absurd. The game contains a large number of Japanese voice samples shouted out in a style similar to that of a game show host. Unlike the previous two titles, Jikkyō Oshaberi Parodius was not created as an arcade game. It was first released on the Super Famicom in 1995 and then ported and updated for the PlayStation and Sega Saturn in 1996.

<i>Sexy Parodius</i> 1996 arcade game by Konami

Sexy Parodius is a 1996 horizontal-scrolling shooter arcade game developed by Konami. It is the fifth installment of the Parodius series. Like the rest of the series, it is a parody of the Gradius series and other Konami games. It also contains sexual level and enemy designs, as well as risqué innuendo. Many level bosses are women in various erotic costumes or various states of undress.

<i>Gradius II</i> 1988 video game

Gradius II is a side-scrolling shooter game developed and published by Konami. Originally released for the arcades in Japan in 1988, it is the sequel to original Gradius and was succeeded by Gradius III. Ports of Gradius II were released for the Family Computer, PC-Engine Super CD-ROM², and the X68000 in Japan. The original arcade version is also included in the Gradius Deluxe Pack compilation for the PlayStation and Sega Saturn and in Gradius Collection for the PlayStation Portable.

<i>Gradius Advance</i> 2001 video game

Gradius Advance is a horizontally scrolling shooter handheld video game developed by Mobile21 and published by Konami in 2001. It was released later in the same month in the United States as Gradius Galaxies and in 2002 in Japan as Gradius Generation. It is the only Gradius title available for the Game Boy Advance. The game's plot is set between Gradius III and Gradius Gaiden. Bacterion was developing a powerful weapon to use against the planet Gradius, but it was destroyed. A few years later it crashed on a planet and the planet gradually changed into a mechanical fortress. The planet Gradius then sent the Vic Viper to stop it.

<i>Parodius! From Myth to Laughter</i> 1990 video game

Parodius! From Myth to Laughter, released in Japan as Parodius Da! Shinwa kara Owarai e and outside Japan as Parodius, is a shoot 'em up arcade video game and the second title in the Parodius series produced by Konami. The European SNES version is also known as Parodius: Non-Sense Fantasy. The gameplay is stylistically very similar to the Gradius series, but the graphics and music are intentionally absurd.

<i>Parodius: The Octopus Saves the Earth</i> 1988 video game

Parodius: The Octopus Saves the Earth, also known as Parodius, is a scrolling shooter video game developed by Konami for the MSX computer and was released in Japan. The game is notable for being the first title in the Parodius series, although it is often confused with its sequel Parodius! From Myth to Laughter. The name itself is a portmanteau of "Gradius" and "Parody" and, eponymously, the game is a parody of the Gradius series of space-based horizontally scrolling shooters. Many of the characters and enemies are derived from that famous shooter series, while other elements are extracted from other Konami titles, such as Antarctic Adventure and TwinBee. This game is of particular note in the series as being heavily infused with Japanese culture and folklore.

<i>Gokujo Parodius</i> 1994 video game

Gokujō Parodius ~Kako no Eikō o Motomete~, translated as Gokujo Parodius – Pursuing the Past Glory and also known as Fantastic Journey, is a 1994 side-scrolling shooter arcade game developed and published by Konami. It is the third entry in their Parodius series, itself a parody spin-off of their Gradius series.

<i>Konami Wai Wai World</i> 1988 video game

Konami Wai Wai World (コナミワイワイワールド), "wai wai" being a Japanese onomatopoeia for a noisy, crowded area, is a 1988 Family Computer platform video game released only in Japan by Konami. The game itself stars various Konami-created characters as well as Mikey and King Kong, who appeared in two Konami-produced, movie-based games.

<i>Wai Wai World 2: SOS!! Parsley Jō</i> 1991 video game

Wai Wai World 2: SOS!! Parsley Jō is a 1991 Famicom platform game released only in Japan by Konami. It is a sequel to Konami Wai Wai World, and stars various Konami characters. It was also re-released for the Wii U Virtual Console on September 2, 2015 in Japan.

<i>Salamander 2</i> 1996 video game

Salamander 2 is a 1996 horizontally scrolling shooter arcade video game developed and published in Japan by Konami. It is the direct sequel to Salamander (1986) and the third game in the Salamander series, which itself is a spin-off of the Gradius franchise. Up to two players control two starships — the Vic Viper and the Super Cobra — as they must destroy the alien race Doom before they wipe out all of the planet Gradius. Gameplay involves shooting down enemies, collecting power-up items, and avoiding collision with projectiles or obstacles.

<i>Gradius Gaiden</i> 1997 video game

Gradius Gaiden is a 1997 horizontal-scrolling shooter video game developed and published for the PlayStation by Konami. Players control one of four different starships in their mission to eradicate the Bacteria army from destroying the planet Gradius. Gameplay involves shooting down enemies, avoiding their projectiles, and collecting power capsules to unlock access to new weapons. It is the fourth mainline entry in the company's Gradius franchise, and the second to be produced specifically for a home console.

<i>Gradius V</i> 2004 video game

Gradius V is a Japanese-developed shoot 'em up video game published by Konami for the Sony PlayStation 2 video game console in 2004. Gradius V was largely developed under contract by Treasure, who had previously worked on Radiant Silvergun and Ikaruga. The game is set predominantly in outer space where players control a fictional spacecraft called Vic Viper through a continuously scrolling background depicting the territories of Bacterian—an evil empire which serves as the player's enemy. Gradius V received overall positive reviews. Critics praised the level design, graphical design and "classic" revival, but criticized the game's difficulty.

<i>Konami Antiques MSX Collection</i> 1997 video game

Konami Antiques MSX Collection is a series of compilations of MSX computer games released by Konami in Japan for the PlayStation and Sega Saturn between 1997 and 1998.

<i>Gradius: The Interstellar Assault</i> 1991 video game

Gradius: The Interstellar Assault, released as Nemesis II: The Return of the Hero in Europe, and Nemesis II in Japan, is the second Game Boy game in the Gradius series. The game was later ported to the Konami GB Collection series of Super Game Boy and Game Boy Color compilations; it can be found in the Japanese Vol. 3 and the European Vol. 4. Like Gradius before it, these versions were renamed Gradius II for the Japanese Vol. 3 and Gradius II: The Return of the Hero for the European Vol. 4.

<i>Nemesis 3: The Eve of Destruction</i> 1989 video game

Nemesis 3: The Eve of Destruction is a 1988 computer game, developed and published by Konami exclusively for the MSX platform in 1988. It was only released in Japan and Europe. The game is part of the long running Gradius series of side-scrolling shooters and is a spin-off of Gradius II: Gofer no Yabou. It is the second game of the series to be released exclusively for the MSX after Nemesis 2. In terms of the story; the game is a sequel to Gradius II, Nemesis 2, and the MSX conversion of Salamander. The game takes place almost 200 years after the crisis with Dr. Venom and James Burton has died in the year 6718. The Vic Viper is replaced by a new ship called the Vixen ; piloted by David Burton, a direct descendant of James who is assisted by his AI Gaudie.

<i>Gradius III</i> 1989 video game

Gradius III is a 1989 scrolling shooter video game developed and published by Konami, originally released for the arcades in Japan and other parts of Asia on December 11, 1989. It is the third game in the Gradius series. The game was ported to the Super Nintendo Entertainment System in Japan in 1990 and North America in 1991, and served as a launch title for the system in North America. The arcade version would never see the light of day in the West until it was included alongside Gradius IV in a two-in-one compilation for the PlayStation 2 and in the Gradius Collection for the PlayStation Portable.

<i>Nemesis 2</i> (MSX) 1987 video game

Nemesis 2 is a side-scrolling shoot 'em up video game released for the MSX computer in 1987 by Konami. The game is a sequel to Nemesis, the MSX version of Gradius, but is unrelated to the arcade game Gradius II. This version was ported to the X68000 computer under the name Nemesis '90 Kai, with some graphical and aural enhancements.


  1. "The Arcade Flyer Archive - Video Game Flyers: Nemesis, Konami (North America)".
  2. "The Arcade Flyer Archive - Video Game Flyers: Nemesis, Konami (International)".
  3. In the X68000 version of Gradius II, switching the title mode to "USA" will change the game's name to Vulcan Venture.
  4. Yip, Spencer (2 March 2010). "Gradius Arc? Color Us Curious, Konami". Retrieved 2010-06-04.
  5. Ishida, Katsuo (30 September 2010). "KONAMI、モバイル「グラディウス・アーク」サービス開始". GAME Watch. Retrieved 2010-10-13.
  6. Ficha de Gradius en P-World
  7. "Cracking the Code: The Konami Code". Retrieved 2010-07-15.
  8. 1 2 3 4 Game Hiyou 9/99
  9. Mielke, James (August 18, 2006). "The Kamiya Touch: An Interview with Clover's Hideki Kamiya". Archived from the original on October 12, 2012. Retrieved 2009-04-06.