Shoot 'em up
|Part of a series on|
Shoot 'em up (also known as shmup or STG) is a subgenre of the shooter genre of video games. In a shoot 'em up, the player character moves forward automatically, often in a flying vehicle such as a spacecraft or aircraft, shooting large numbers of enemies while dodging obstacles. There is no consensus as to which design elements compose a shoot 'em up. Some restrict the definition to games featuring spacecraft and certain types of character movement; others allow a broader definition including characters on foot and a variety of perspectives. Shoot 'em ups call for fast reactions and for the player to memorize levels and enemy attack patterns. "Bullet hell" games are a relatively recent subgenre that features overwhelming numbers of enemy projectiles, often in visually impressive formations.
The genre's origins can be traced back to Spacewar!, one of the earliest computer games, developed in 1962 and eventually released in amusement arcades in the early 1970s. Later in the 1970s, games such as Space Invaders and Asteroids popularized the genre. Shoot 'em ups were popular throughout the 1980s and early 1990s. In the mid-1990s, shoot 'em ups became a niche genre based on design conventions established in the 1980s, and increasingly catered to specialist enthusiasts, particularly in Japan.
A "shoot 'em up", also known as a "shmup" or "STG" (the common Japanese abbreviation for "shooting games"), is a game in which the protagonist combats a large number of enemies by shooting at them while dodging their fire. The controlling player must rely primarily on reaction times to succeed. Beyond this, critics differ on exactly which design elements constitute a shoot 'em up. Some restrict the genre to games featuring some kind of craft, using fixed or scrolling movement. Others widen the scope to include games featuring such protagonists as robots or humans on foot, as well as including games featuring "on-rails" (or "into the screen") and "run and gun" movement. Mark Wolf restricts the definition to games featuring multiple antagonists ("'em" being short for "them"), calling games featuring one-on-one shooting "combat games". Formerly, critics described any game where the primary design element was shooting as a "shoot 'em up", but later shoot 'em ups became a specific, inward-looking genre based on design conventions established in those shooting games of the 1980s.
Shoot 'em ups are a subgenre of shooter game, in turn a type of action game. These games are usually viewed from a top-down or side-view perspective, and players must use ranged weapons to take action at a distance. The player's avatar is typically a vehicle under constant attack. Thus, the player's goal is to shoot as quickly as possible at anything that moves or threatens him. In some games, the player's character can withstand some damage; in others, a single hit will result in his destruction. The main skills required in shoot 'em ups are fast reactions and memorising enemy attack patterns. Some games feature overwhelming numbers of enemy projectiles and the player has to memorise their patterns to survive. These games belong to one of the fastest-paced video game genres.
Large numbers of enemy characters are typically featured. These enemies may behave in a certain way dependent on their type, or attack in formations that the player can learn to predict. The basic gameplay tends to be straightforward and many games offset this with boss battles and a variety of weapons. Shoot 'em ups rarely have realistic physics. Characters can instantly change direction with no inertia, and projectiles move in a straight line at constant speeds. The player's character can collect "power-ups" which may afford the character greater protection, an "extra life", or upgraded weaponry. Different weapons are often suited to different enemies, but these games seldom keep track of ammunition. As such, players tend to fire indiscriminately, and their weapons only damage legitimate targets.
Shoot 'em ups are categorized by design elements, particularly viewpoint and movement:
Fixed shooters (such as Space Invaders) restrict the protagonist to a single axis of motion, enemies attack in a single direction (such as descending from the top of the screen), and each level is contained within a single screen. These games are sometimes called "gallery shooters". Atari's Centipede is a hybrid, in that the player can move freely, but that movement is constrained to a small area at the bottom of the screen, and the game otherwise meets the fixed shooter definition.
Rail shooters limit the player to moving around the screen while the game follows a specific route; these games often feature an "into the screen" viewpoint, with which the action is seen from behind the player character, and moves "into the screen", while the player retains control over dodging. Examples include Space Harrier (1985), Captain Skyhawk (1990), Star Wars: Rebel Assault (1993), Panzer Dragoon (1995), Star Fox 64 (1997), and Sin and Punishment (2000). Light-Gun games that are "on-rails" are not in the shoot-em-up category but the FPS category, and the term has also been applied to scripted events in first-person shooters such as Call of Duty.
Tube shooters feature craft flying through an abstract tube.
Scrolling shooters include vertical or horizontal scrolling games.
- Vertically scrolling shooters: In a vertically scrolling shoot 'em up (or "vertical scroller"), the action is viewed from above and scrolls up (or very occasionally down) the screen.
- Horizontally scrolling shooters: In a "horizontal shooter" or "side-scrolling shooter", the action is viewed side-on and scrolls horizontally.
- Isometrically scrolling shooters: A small number of scrolling shooters, such as Sega's Zaxxon, feature an isometric point of view.
Multidirectional shooters feature 360 degree movement where the protagonist may rotate and move in any direction. Multidirectional shooters with one joystick for movement and one joystick for firing in any direction independent of movement are called "twin-stick shooters."
Bullet hell (弾幕 danmaku, literally "barrage" or "bullet curtain") is a shoot 'em up in which the entire screen is often almost completely filled with enemy bullets. This type is also known as "curtain fire", "manic shooters" or "maniac shooters". This style of game originated in the mid-1990s, and is an offshoot of scrolling shooters.
Cute 'em ups feature brightly coloured graphics depicting surreal settings and enemies. Newer, particularly Japanese, cute 'em ups may employ overtly sexual characters and innuendo. Cute 'em ups tend to have unusual, oftentimes completely bizarre opponents for the player to fight, with the Parodius franchise being an example.
Run and gun (or "run 'n' gun") describes a shoot 'em up in which the protagonist fights on foot, perhaps with the ability to jump. Run and gun games may use side scrolling, vertical scrolling or isometric viewpoints and may feature multidirectional movement.
Origins and rise
The genre's exact origins are a matter of some confusion. Video game journalist Brian Ashcraft pinpoints Spacewar! (one of the very earliest computer games) as the first shoot 'em up, but the later Space Invaders is more frequently cited as the "first" or "original" in the genre. Spacewar! was developed at the Massachusetts Institute of Technology in 1961, for the amusement of the developers; it was, however, remade four times as an arcade game in the early to mid-1970s. The game featured combat between two spacecraft.
However, it was not until 1978's seminal Space Invaders, created by Nishikado at Japan's Taito Corporation, that the shooter genre became prolific. Space Invaders pitted the player against multiple enemies descending from the top of the screen at a constantly increasing rate of speed. The game used alien creatures inspired by The War of the Worlds (by H. G. Wells) because the developers were unable to render the movement of aircraft; in turn, the aliens replaced human enemies because of moral concerns (regarding the portrayal of killing humans) on the part of Taito Corporation. As with subsequent shoot 'em ups of the time, the game was set in space as the available technology only permitted a black background. The game also introduced the idea of giving the player a number of "lives". It popularised a more interactive style of gameplay with the enemies responding to the player-controlled cannon's movement, and it was the first video game to popularise the concept of achieving a high score, being the first to save the player's score. The aliens of Space Invaders return fire at the protagonist, making them the first arcade game targets to do so. It set the template for the shoot 'em up genre, and has influenced most shooting games released since then.
Golden age and refinement
In 1979, Namco's Galaxian—"the granddaddy of all top-down shooters", according to IGN—was released. Its use of colour graphics and individualised antagonists were considered "strong evolutionary concepts" among space ship games. That same year saw the release of SNK's debut shoot 'em up Ozma Wars, notable for being the first action game to feature a supply of energy, resembling a life bar, a mechanic that has now become common in the majority of modern action games. It also featured vertically scrolling backgrounds and enemies.
In 1981, Defender established scrolling in shoot 'em ups, offering horizontally extended levels. Unlike most later games in the genre, the player could move in either direction. The game's use of scrolling helped remove design limitations associated with the screen, and though the game's minimap feature had been introduced before, Defender integrated it into the gameplay in a more essential manner. Konami's Scramble, released in 1981, is a side-scrolling shooter with forced scrolling. It was the first scrolling shooter to offer multiple, distinct levels. Atari's Tempest, released in 1981, is one of the earliest tube shooters and an early attempt to incorporate a 3D perspective into shooter games. Tempest ultimately went on to influence major rail shooters.
Vertical scrolling shooters emerged around the same time. Namco's Xevious, released in 1982, is frequently cited as the first vertical scrolling shooter and, although it was in fact preceded by several other games of that type, it is considered one of the most influential. Xevious is also the first to convincingly portray realistic landscapes as opposed to purely science fiction settings. While Asteroids (1979) allowed the player to rotate the game's spacecraft, 1982's highly acclaimed Robotron: 2084 was most influential on subsequent multi-directional shooters.
Sega's Space Harrier, a rail shooter released in 1985, broke new ground graphically and its wide variety of settings across multiple levels gave players more to aim for than high scores. 1985 also saw the release of Konami's Gradius, which gave the player greater control over the choice of weaponry, thus introducing another element of strategy. The game also introduced the need for the player to memorise levels in order to achieve any measure of success. Gradius, with its iconic protagonist, defined the side-scrolling shoot 'em up and spawned a series spanning several sequels. The following year saw the emergence of one of Sega's forefront series with its game Fantasy Zone. The game received acclaim for its surreal graphics and setting and the protagonist, Opa-Opa, was for a time considered Sega's mascot. The game borrowed Defender's device of allowing the player to control the direction of flight and along with the earlier TwinBee (1985), is an early archetype of the "cute 'em up" subgenre. R-Type, an acclaimed side-scrolling shoot 'em up, was released in 1987 by Irem, employing slower paced scrolling than usual, with difficult levels calling for methodical strategies. 1990's Raiden was the beginning of another acclaimed and enduring series to emerge from this period.
Shoot 'em ups such as SNK's Ikari Warriors (1986) featuring characters on foot, rather than spacecraft, became popular in the mid-1980s in the wake of action movies such as Rambo: First Blood Part II. The origins of this type go back to Sheriff by Nintendo, released in 1979. Taito's Front Line (1982) established the upwards-scrolling formula later popularized by Commando, in 1985. Commando also drew comparisons to Rambo and indeed contemporary critics considered military themes and protagonists similar to Rambo or Schwarzenegger prerequisites for a shoot 'em up, as opposed to an action-adventure game. In 1986, Arsys Software released WiBArm, a shooter that switched between a 2D side-scrolling view in outdoor areas to a fully 3D polygonal third-person perspective inside buildings, while bosses were fought in an arena-style 2D battle, with the game featuring a variety of weapons and equipment. In 1987, Square's 3-D WorldRunner was an early stereoscopic 3-D shooter played from a third-person perspective, followed later that year by its sequel JJ, and the following year by Space Harrier 3-D which used the SegaScope 3-D shutter glasses. That same year, Sega's Thunder Blade switched between both a top-down view and a third-person view, and introduced the use of force feedback, where the joystick vibrates. Also in 1987, Konami created Contra as an coin-op arcade game that was particularly acclaimed for its multi-directional aiming and two player cooperative gameplay. However, by the early 1990s and the popularity of 16-bit consoles, the scrolling shooter genre was overcrowded, with developers struggling to make their games stand out (one exception being the inventive Gunstar Heroes, by Treasure).
Bullet hell and niche appeal
This article needs to be updated.(August 2017)
A new type of shoot 'em up emerged in the early 1990s: variously termed "bullet hell", "manic shooters", "maniac shooters" and danmaku (弾幕, "barrage"), these games required the player to dodge overwhelming numbers of enemy projectiles and called for still more consistent reactions from players. Bullet hell games arose from the need for 2D shoot 'em up developers to compete with the emerging popularity of 3D games: huge numbers of missiles on screen were intended to impress players. Toaplan's Batsugun (1993) provided the prototypical template for this new breed, with Cave (formed by former employees of Toaplan, including Batsugun's main creator Tsuneki Ikeda, after the latter company collapsed) inventing the type proper with 1995's DonPachi. Bullet hell games marked another point where the shoot 'em up genre began to cater to more dedicated players. Games such as Gradius had been more difficult than Space Invaders or Xevious, but bullet hell games were yet more inward-looking and aimed at dedicated fans of the genre looking for greater challenges. While shooter games featuring protagonists on foot largely moved to 3D-based genres, popular, long-running series such as Contra and Metal Slug continued to receive new sequels. Rail shooters have rarely been released in the new millennium, with only Rez and Panzer Dragoon Orta achieving cult recognition.
Treasure's shoot 'em up, Radiant Silvergun (1998), introduced an element of narrative to the genre. It was critically acclaimed for its refined design, though it was not released outside Japan and remains a much sought after collector's item. Its successor Ikaruga (2001) featured improved graphics and was again acclaimed as one of the best games in the genre. Both Radiant Silvergun and Ikaruga were later released on Xbox Live Arcade. The Touhou Project series spans 22 years and 27 games as of 2018 and was listed in the Guinness World Records in October 2010 for being the "most prolific fan-made shooter series". The genre has undergone something of a resurgence with the release of the Xbox 360, PlayStation 3 and Wii online services, while in Japan arcade shoot 'em ups retain a deep-rooted niche popularity. Geometry Wars: Retro Evolved was released on Xbox Live Arcade in 2005 and in particular stood out from the various re-releases and casual games available on the service. The PC has also seen its share of dōjin shoot 'em ups like Crimzon Clover, Jamestown: Legend of the Lost Colony, Xenoslaive Overdrive, and the eXceed series. However, despite the genre's continued appeal to an enthusiastic niche of players, shoot 'em up developers are increasingly embattled financially by the power of home consoles and their attendant genres.
- Davies, Jonti. The Shooting Never Stops Archived 2012-04-02 at the Wayback Machine.. GameSpy. 30 July 2008.
- Carless, Simon. Final Form On Jamestown's Origins, Mechanics Archived 2011-09-08 at the Wayback Machine.. Game Set Watch. 5 April 2011.
- Buchanan, Levi, Top 10 Classic Shoot 'Em Ups Archived 2012-02-16 at the Wayback Machine., IGN, April 8, 2008, May 26, 2009
- Beck, Ian (May 19, 2006). "Jets'n'Guns". Inside Mac Games. Archived from the original on December 6, 2008. Retrieved July 20, 2008.
- Ashcraft, p. 70
- Bielby, Matt, "The Complete YS Guide to Shoot 'Em Ups", Your Sinclair, July, 1990 (issue 55), p. 33
- Game Genres: Shmups, Professor Jim Whitehead, January 29, 2007. Accessed June 17, 2008
- Provo, Frank, Bloody Wolf Archived 2008-12-12 at the Wayback Machine., GameSpot, July 7, 2007. Accessed June 17, 2008
- Mark J. P. Wolf (2008). The video game explosion: a history from PONG to PlayStation and beyond. ABC-CLIO. p. 272. ISBN 0-313-33868-X. Archived from the original on 2012-11-14. Retrieved 2011-04-10.
- Rollings, Andrew; Ernest Adams (2006). Fundamentals of Game Design. Prentice Hall. Archived from the original on 2009-02-17.
- Parkin, Simon (September 21, 2006). "Gradius Collection". Eurogamer. Archived from the original on July 3, 2009. Retrieved February 14, 2009.
- Ashcraft, p. 66
- Provo, Frank Galaga '90 Archived 2008-12-12 at the Wayback Machine., GameSpot, August 10, 2007. Accessed June 17, 2008
- Goldstein, Hilary, Panzer Dragoon Orta Archived 2009-03-07 at the Wayback Machine., IGN, January 10, 2003, July 17, 2008
- Kalata, Kurt, Space Harrier, Hardcore Gaming 101. Accessed February 02, 2010
- Ashcraft, Brian (2008), Arcade Mania! The Turbo Charged World of Japan's Game Centers, Kodansha International, p. 147
- "Call of Duty: Black Ops Review". Game Rant. 2010-11-11. Archived from the original on 2010-11-12. Retrieved 2010-11-27.
it becomes a little disappointing when you're forced to sit there and watch scripted walkthroughs of story moments. Going to the Pentagon is something that should be pretty exciting, but it's essentially a rail-shooter without the shooting.
- Robert Howarth (November 8, 2007). "Call of Duty 4 First Impressions". Voodoo Extreme. IGN. Archived from the original on November 11, 2007. Retrieved 2011-05-07.
- Reed, Kristan, Gyruss Archived 2009-08-05 at the Wayback Machine., Eurogamer, April 19, 2007. Accessed February 17, 2009
- Smith, Rachael, "Sidewize", Your Sinclair, October 1987 (issue 22), p. 38
- Onyett, Charles (February 13, 2006). "Crystal Quest". IGN. Archived from the original on July 22, 2016. Retrieved June 17, 2008.
- McAllister, Graham (March 30, 2011). "A Guide To iOS Twin Stick Shooter Usability". Gamasutra. Think Services. Archived from the original on April 25, 2014. Retrieved March 5, 2014.
- Yin-Poole, Wesley (December 9, 2013). "Microsoft's ID@Xbox policy means this indie twin-stick shooter can't launch on Xbox One". Eurogamer. Gamer Network. Archived from the original on March 5, 2014. Retrieved March 5, 2014.
- Sheffield, Brandon, Q&A: Capcom's Kujawa On Revisiting Classics, Bullet Hell Archived 2008-06-23 at the Wayback Machine., Gamasutra, April 22, 2008. Accessed March 2, 2009
- Ashcraft, p. 77
- Ashcraft, p. 82
- Dunham, Jeremy, First Look: Alien Hominid Archived 2008-12-24 at the Wayback Machine., IGN, July 27, 2004. Accessed June 17, 2008
- Bielby, Matt, "The YS Complete Guide To Shoot-'em-ups Part II", Your Sinclair, August 1990 (issue 56), p. 19
- Ashcraft, p. 72
- "The Next Generation 1996 Lexicon A to Z: Shooter". Next Generation. No. 15. Imagine Media. March 1996. p. 40.
The first shooter is generally acknowledged to be Space Invaders.
- Buchanan, Levi, Space Invaders Archived 2008-12-08 at the Wayback Machine., IGN, March 31, 2003. Accessed June 14, 2008
- Surette, Tim, Gaming pioneer passes away Archived 2008-12-12 at the Wayback Machine., GameSpot, June 7, 2006. Accessed June 16, 2008
- Edwards, Benj. "Ten Things Everyone Should Know About Space Invaders". 1UP.com. Retrieved 2008-07-11.
- Retro Gamer Staff. "Nishikado-San Speaks". Retro Gamer. No. 3. Live Publishing. p. 35.
- Geddes, Ryan; Hatfield, Daemon (2007-12-10). "IGN's Top 10 Most Influential Games". IGN. Archived from the original on 2008-07-23. Retrieved 2008-07-11.
- Kevin Bowen. "The Gamespy Hall of Fame: Space Invaders". GameSpy. Archived from the original on 2008-04-08. Retrieved 2010-01-27.
- Craig Glenday, ed. (2008-03-11). "Record Breaking Games: Shooting Games Roundup". Guinness World Records Gamer's Edition 2008. Guinness World Records. Guinness. pp. 106–107. ISBN 978-1-904994-21-3.
- "Players Guide To Electronic Science Fiction Games". Electronic Games. Vol. 1 no. 2. March 1982. pp. 34–45 . Archived from the original on 2 April 2012. Retrieved 1 February 2012.
- "Essential 50: Space Invaders". 1UP.com. Retrieved 2011-03-26.
- Buchanan, Levi.Galaxian Mini Archived 2011-07-13 at the Wayback Machine., IGN, April 21, 2003. Accessed June 17, 2008
- "Arcade Games". Joystick. 1 (1): 10. September 1982.
- Playing With Power: Great Ideas That Have Changed Gaming Forever, 1UP
- The History of SNK Archived 2012-05-14 at the Wayback Machine., GameSpot. Accessed February 16, 2009
- Stearny, Mark (September 1982). "The Evolution of Space Games: How We Got From Space Invaders to Zaxxon". JoyStik (1): 8–29.
- Cuciz, David (May 2001). "Hall of Fame: Defender". GameSpy. Archived from the original on 2005-03-26. Retrieved 2009-12-06.
- Roper, Chris, The Games of Atari Classics Evolved: Part 2 Archived 2007-10-29 at the Wayback Machine., IGN, October 22, 2007. Accessed June 17, 2008
- Terminator 3: The Redemption Archived 2011-07-16 at the Wayback Machine., Yahoo Games!. Accessed March 2, 2009
- Leo, Jonathan, "Rez HD", GameAxis Unwired, March 2008, p. 47
- Ashcraft, p. 75
- Mielke, James, Asteroids Review Archived 2011-09-20 at the Wayback Machine.,'GameSpot, November 19, 1998. Accessed February 17, 2009
- Gerstmann, Jeff, Robotron: 2084 Review[permanent dead link], GameSpot, December 20, 2005. Accessed February 17, 2009
- Staff, Top 10 Tuesday: Game Designers Archived 2012-02-14 at the Wayback Machine., IGN. Accessed February 17, 2009
- Buchanan, Levi, Space Harrier Retrospective Archived 2011-07-13 at the Wayback Machine., IGN, September 5, 2008. Accessed February 17, 2009
- Maragos, Nich, Space Harrier (PS2), 1UP.com, January 1, 2000. Accessed February 17, 2009
- Ashcraft, p. 76
- Kasavin, Greg, Gradius Collection Review[permanent dead link], GameSpot, June 7, 2006. Accessed February 12, 2009
- Fahs, Travis, Fantasy Zone Retrospective Archived 2011-07-13 at the Wayback Machine., IGN, October 1, 2008. Accessed February 13, 2009
- Kalata, Kurt, Fantasy Zone Archived 2010-01-16 at the Wayback Machine., Hardcore Gaming 101. Accessed February 02, 2010
- Todd, Brett, R-Type Dimensions Review[permanent dead link], GameSpot, February 7, 2009. Accessed February 13, 2009
- Navarro, ALex, Raiden Review Archived 2011-09-20 at the Wayback Machine., GameSpot, November 17, 2004. Accessed February 13, 2009
- Buchanan, Levi, Raiden Archived 2009-07-24 at the Wayback Machine., IGN, February 17, 2004. Accessed February 13, 2009
- Segre, Nicole, "Commando," Sinclair User, February 1986 (issue 47)
- John Szczepaniak. "Retro Japanese Computers: Gaming's Final Frontier". Hardcore Gaming 101. p. 4. Archived from the original on 2011-01-13. Retrieved 2011-03-16. Reprinted from "Retro Japanese Computers: Gaming's Final Frontier", Retro Gamer (67), 2009
- 3-D WorldRunner at AllGame
- JJ: Tobidase Daisakusen Part II [Japanese] at AllGame
- Space Harrier 3-D at AllGame
- Thunder Blade at the Killer List of Videogames
- IGN's Top 100 Games Archived 2010-03-12 at the Wayback Machine., IGN, July 25, 2005. Accessed February 19, 2009
- Curtains for You: The History of Bullet Hell:The Birth of Bullet Hell, and the Rise of Cave
- Bullet hell - Glitchwave video games database
- Bullet Hell
- GAMES THAT DEFINED THE SHMUPS GENRE GAMES THAT DEFINED THE SHMUPS GENRE
- Retro Game of the Club (RGClub): Round 9 - Batsugun!
- Red Parsley: Arcade Shmups #12
- 1CC Log for Shmups: Batsugun (Saturn)
- Good bullet hell shmups to emulate? : shmups - Reddit
- DoDonPachi Resurrection: The History
- bullet hell | The Blog That Changed The World
- Batsugun – Hardcore Gaming 101
- The joy of bullet hell - Destructoid
- Sega-16 – Grind Stormer
- Lttp: Castle Shikigami 2 and bullet hell games.
- PressReader - Retro Gamer: 2017-12-28 - Ultimate Guide: Flying Shark
- bullet hell | Gaming History 101
- Transnational Contexts of Culture, Gender, Class, and Colonialism in ...
- The Danmaku Game as a New Optical Art, Part I | Rhizome
- Favorite PC-98 game? : touhou - Reddit [–]drakeirving
- Ashcraft, pp. 78-80
- Ashcraft, pp. 77-78
- Magrino, Tom, Contra conquering DS Archived 2011-09-19 at the Wayback Machine., GameSpot, June 20, 2007. Accessed February 17, 2009
- Staff, Contra Q&A Archived 2011-09-20 at the Wayback Machine., GameSpot, October 1, 2002. Accessed February 17, 2009
- Bozon, Mark, Metal Slug Anthology Review Archived 2009-02-14 at the Wayback Machine., IGN, December 20, 2006. Accessed February 17, 2009
- Brudwig, Erik, Rez HD is Coming Archived 2011-07-13 at the Wayback Machine., IGN, January 22, 2008. Accessed February 17, 2009
- Buchanan, Levi, Fond Memories: Radiant Silvergun Archived 2011-07-13 at the Wayback Machine., IGN, April 7, 2008. Accessed February 13, 2009
- McCarthy, Dave, The Best Games That Never Came out in Britain Archived 2009-01-30 at the Wayback Machine., IGN, January 26, 2009, Accessed February 13, 2009
- Staff, Top 10 Tuesday: 2D Space Shooters Archived 2009-09-03 at the Wayback Machine., IGN, March 6, 2007. Accessed February 13, 2009
- "Most prolific fan-made shooter series". Guinness World Records. Archived from the original on 2013-04-24. Retrieved 2011-09-24.
- Ashcraft, p. 88
- Gouskos, Carrie, Geometry Wars: Retro Evolved Review Archived 2009-01-30 at the Wayback Machine., GameSpot, November 23, 2005. Accessed February 13, 2009
- "State of the Shoot ëEm Up - Edge Magazine". Next-gen.biz. 2008-11-17. Retrieved 2011-09-06.
- Ashcraft, Brian, (2008) Arcade Mania! The Turbo-Charged World of Japan's Game Centers, (Kodansha International)