Tower defense

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Strategy video games

Tower defense (TD) is a subgenre of strategy video game where the goal is to defend a player's territories or possessions by obstructing the enemy attackers, usually achieved by placing defensive structures on or along their path of attack. [1] This typically means building a variety of different structures that serve to automatically block, impede, attack or destroy enemies. Tower defense is seen as a subgenre of real-time strategy video games, due to its real-time origins, [2] [3] though many modern tower defense games include aspects of turn-based strategy. Strategic choice and positioning of defensive elements is an essential strategy of the genre.

A strategy video game is a video game genre that focuses on skillful thinking and planning to achieve victory. It emphasizes strategic, tactical, and sometimes logistical challenges. Many games also offer economic challenges and exploration. They are generally categorized into four sub-types, depending on whether the game is turn-based or real-time, and whether the game focuses on strategy or tactics.

Real-time strategy (RTS) is a sub-genre of strategy video games in which the game does not progress incrementally in turns. This is distinguished from turn-based strategy (TBS), in which all players take turns when playing.

Video game electronic game that involves interaction with a user interface to generate visual feedback on a video device such as a TV screen or computer monitor

A video game is an electronic game that involves interaction with a user interface to generate visual feedback on a two- or three-dimensional video display device such as a TV screen, virtual reality headset or computer monitor. Since the 1980s, video games have become an increasingly important part of the entertainment industry, and whether they are also a form of art is a matter of dispute.


Ryan Clements of IGN attributes the popularity of such games to psychology and human vulnerability. [4] Tower defense, according to Clements, "plays off of our need for security, ownership, and a desire to protect the people closest to us" arising from a need to create intrinsic value through "ownership over things", "personal space" and to "repel our fears and insecurities". [4]

<i>IGN</i> American entertainment website

IGN is an American video game and entertainment media website operated by IGN Entertainment Inc., a subsidiary of Ziff Davis, itself wholly owned by j2 Global. The company is located in San Francisco's SOMA district and is headed by its former editor-in-chief, Peer Schneider. The IGN website was the brainchild of media entrepreneur Chris Anderson and launched on September 29, 1996. It focuses on games, films, television, comics, technology, and other media. Originally a network of desktop websites, IGN is now also distributed on mobile platforms, console programs on the Xbox and PlayStation, FireTV, Roku, and via YouTube, Twitch, Hulu, and Snapchat.



The tower defense genre can trace its lineage back to the golden age of arcade video games in the 1980s. The object of the arcade game Space Invaders, released in 1978, was to defend the player's territory (represented by the bottom of the screen) against waves of incoming enemies. The game featured shields which could be used to strategically obstruct enemy attacks on the player and assist the player in defending their territory, though not to expressly protect the territory. The 1980 game Missile Command changed that by giving shields a more strategic role. In the game, players could obstruct incoming missiles, and there were multiple attack paths in each attack wave. [5] Missile Command was also the first of its kind to make use of a pointing device, a trackball, enabling players to use a crosshair. The innovation was ahead of its time and anticipated the genre's later boom, which was paved by the wide adoption of the computer mouse. Additionally, in Missile Command, the sole target of the attackers is the base, not a specific player character. For these reasons, some regard it as the first true game in the genre. [5]

The golden age of arcade video games was the era when arcade video games entered pop culture and became a dominant cultural force. The exact time period is disputed, but key moments include the release of Space Invaders in 1978 and the vector-based Asteroids in 1979—moments made possible by the increase in power and decrease in cost of computing technology. This led to the rise of both video game arcades and video games in other media, such as songs, cartoons, and movies like 1982's TRON. Other iconic games from this era include Pac-Man, Defender, Galaga, Donkey Kong, and Centipede.

<i>Space Invaders</i> Landmark fixed shooter arcade video game from 1978

Space Invaders is a 1978 arcade game created by Tomohiro Nishikado. It was manufactured and sold by Taito in Japan, and licensed in the United States by the Midway division of Bally. Within the shooter genre, Space Invaders was the first fixed shooter and set the template for the shoot 'em up genre. The goal is to defeat wave after wave of descending aliens with a horizontally moving laser to earn as many points as possible.

<i>Missile Command</i> Atari tower defense arcade video game first released in 1980

Missile Command is a 1980 arcade game developed and published by Atari, Inc. and licensed to Sega for European release. It was designed by Dave Theurer, who also designed Atari's vector graphics game Tempest from the same year. The 1981 Atari 2600 port of Missile Command by Rob Fulop sold over 2.5 million copies.

While later arcade games like Defender (1981) and Choplifter (1982) lacked the strategy element of Missile Command, they began a trend of games that shifted the primary objective to defending non-player items. In these games, defending non-players from waves of attackers is key to progressing. Parker Brothers' 1982 title Star Wars: The Empire Strikes Back for the Atari 2600 was one of the first tie-ins to popularize the base defense style. The concept of waves of enemies attacking the base in single file (in this case AT-ATs) proved a formula that was subsequently copied by many games as the shift from arcade to PC gaming began. Players were now able to choose from different methods of obstructing attackers' progress. [6]

<i>Defender</i> (1981 video game) 1981 video game

Defender is an arcade video game developed and released by Williams Electronics in 1981. A horizontally scrolling shoot 'em up, the game is set on an unnamed planet where the player must defeat waves of invading aliens while protecting astronauts. Development was led by Eugene Jarvis, a pinball programmer at Williams; Defender was Jarvis' first video game project and drew inspiration from Space Invaders and Asteroids.

<i>Choplifter</i> Video game first made in 1982 for the Apple II computer

Choplifter is a 1982 Apple II game developed by Dan Gorlin and published by Brøderbund. It was ported to Atari 5200, Atari 8-bit family, ColecoVision, Commodore 64, Commodore VIC-20, MSX and Thomson computers. Graphically enhanced versions for the Atari 8-bit family and Atari 7800 were published in 1988 by Atari Corporation.

Parker Brothers American toy and game manufacturer

Parker Brothers was an American toy and game manufacturer which later became a brand of Hasbro. More than 1,800 games were published under the Parker Brothers name since 1883. Among its products were Monopoly, Cluedo, Sorry!, Risk, Trivial Pursuit, Ouija, Aggravation, Bop It, and Probe. The trade name became defunct with former products being marketed under the "Hasbro Gaming" label. However, in 2017, Hasbro revived the brand with the release of several new games which bear similarities with those of some of its previous, better-known products.

Green House, a popular 1982 handheld game by Nintendo Nintendo Game&Watch - Green House.jpg
Green House, a popular 1982 handheld game by Nintendo

Nintendo's popular 1980s Game & Watch hand held games featured many popular precursors. With their fixed sprite cells with binary states, games with waves of attackers following fixed paths were able to make use of the technical limitations of the platform yet proved simple and enjoyable to casual gamers. Vermin (1980), one of the first, had players with defending the garden (a theme followed by many later games) from relentless horde of moles. The following years saw a flood of similar titles, including Manhole (1981), Parachute (1981), and Popeye (1981). 1982 saw multiple titles with the primary object of protecting buildings from burning: Fire Attack, Oil Panic and Mickey & Donald. The later titles utilized multiple articulating screens to increase the difficulty for players. With two screens these games introduced basic resource management (e.g. oil and water), forcing players to multi-task. Green House (1982) was another popular two screen game in which players use clouds of pesticide spray to protect flowers from waves of attacking insects. Despite the early rush of archetypal titles, ultimately there was a general decline in fixed-cell games, due to their technical limitations, simplistic gameplay, and the rise of personal computers and handhelds the Game Boy; correspondingly, this genre also declined. A rare exception was Safebuster (1988 multi-screen) in which the player protects a safe from a thief trying to blow it up.

Articulating screen

An articulating screen is a liquid-crystal display (LCD) which is not fixed, but rather can be repositioned using a hinge or pivot. The articulating screen is known under different other names such as flip-out screen, flip screen, adjustable screen, articulated screen, or hinged screen. According to the way it moves, there are three main types:

  1. The LCD moves around one axis, so that it only tilts. It is called tilting screen or tiltable screen.
  2. The LCD moves around two axes which are at a right angle to each other, so that the screen both tilts and swivels. This type is called swivel screen. Other names for this type are vari-angle screen, fully articulated screen, fully articulating screen, rotating screen, multi-angle screen, variable angle screen, flip-out-and-twist screen, twist-and-tilt screen and swing-and-tilt screen.
  3. The LCD moves into a variety of angles; it tilts horizontally and vertically and also rotates to a certain extent while staying aligned with the lens axis. It still can not be turned all the way up, down or to the side to be seen from the front of the camera for self-portraits. This type of articulating screen is called cross-tilt screen, flexible-tilt screen or flex-tilt screen.
Game Boy 1989 portable video game console

The Game Boy is an 8-bit handheld game console developed and manufactured by Nintendo. The first handheld in the Game Boy family, it was first released in Japan on April 21, 1989, then North America, three months later, and lastly in Europe, nearly a year after. It was designed by the same team that developed the Game & Watch and several Nintendo Entertainment System games: Satoru Okada, Gunpei Yokoi, and Nintendo Research & Development 1.

By the mid 1980s, the strategy elements began to further evolve. Early PC gaming examples include the 1984 Commodore 64 titles Gandalf the Sorcerer, a shooter with tower defense elements, and Imagine Software's 1984 release Pedro . Pedro, a garden defense game, introduced new gameplay elements, including different enemy types as well as the ability to place fixed obstructions, and to build and repair the player's territory. [7]

Imagine Software former British video games developer

Imagine Software was a British video games developer based in Liverpool which existed briefly in the early 1980s, initially producing software for the ZX Spectrum and VIC-20. The company rose quickly to prominence and was noted for its polished, high-budget approach to packaging and advertising, as well as its self-promotion and ambition.

<i>Pedro</i> (video game) 1984 video game

Pedro is a computer game developed by Frank Johnson, Aidan Rajswing, Bryce Ducharm, Andrew Impson, Brian Carpenter and Steve Cain for the ZX Spectrum and released by Imagine Software in 1984. The game uses oblique projection to give the impression of three dimensional graphics.

Modern genre emerges

Rampart , released in 1990 is generally considered to have established the prototypical tower defense. [8] Rampart introduced player placed defenses that automatically attack incoming enemies. In addition, it has distinct phases of build, defend and repair. These are now staple gameplay elements of many games in the genre. It was also one of the first multiplayer video games of its kind. [9]

While Rampart was popular, similar games were rarely seen until the widespread adoption of the computer mouse on the PC. The DOS title Ambush at Sorinor (1993) was a rare exception from this era. [9] Tower defense gameplay also made an appearance on consoles with several minigames in the Final Fantasy series, including a tower-defense minigame in Final Fantasy VI (1994) [10] and the Fort Condor minigame in Final Fantasy VII (1997), which was also one of the first to feature 3D graphics. Dungeon Keeper (1997) had players defend the Dungeon Heart, a gigantic gem at the centre of your dungeon, which, if destroyed, would cause the player to lose the game. [11] A central theme of the 3D first person shooter Turok 2: Seeds of Evil (1998) was to defend Energy Totems against hordes of attackers. [12]

As real-time strategy games gained popularity in PC gaming, many introduced tower defense modes in their gameplay, particularly in multiplayer. In February 2006, the custom maps for Wacraft III (2002), Element Tower Defense (Element TD) and Gem Tower Defense, which were created in Warcraft III World Editor, almost single-handedly rekindled the genre. [8] These titles would also bring role-playing elements to the genre for the first time.

2007-2008 boom

Between 2007 and 2008, the genre became a phenomenon, due in part to the popularity of the tower defense mode in real time strategy games, but mainly due to the rise of Adobe Flash independent developers as well as the emergence of major smartphone app stores from Apple and Google. The first stand-alone browser games emerged in 2007. [13] Among them were the extremely popular titles Flash Element Tower Defense released in January, [14] Desktop Tower Defense released in March [15] [16] and Antbuster released in May. [17] [18] Desktop Tower Defense earned an Independent Games Festival award, [19] and its success led to a version created for the mobile phone by a different developer. [20] Another significant Flash title released in 2008 was GemCraft . [21] Handheld game console were not ignored in the boom and titles included Lock's Quest and Ninjatown released in September and October respectively. [22]

With the arrival of Apple's App Store tower defense developers adapted quickly to the touchscreen interface and the titles were among the most downloaded, many of them ported directly from Flash. Among the more notable include Bloons TD 4 (2009) which sold more than a million copies on iOS. [23]

The genre's success also led to new releases on PC and video game consoles. Popular 2008 titles included PixelJunk Monsters released in January, Defense Grid: The Awakening [24] and Savage Moon in December. [8] GauntNet was released in April 2009. [25] Plants vs. Zombies released in May 2009 was another highly popular tower defense which became a successful series on mobile devices. [26]

A new breed of 3D games

By the end of the boom, most tower defense games were still stuck in the side scrolling, isometric, or top-down perspective graphical medium. Iron Grip: Warlord , released in November, 2008 unsuccessfully pioneered the first person perspective shooter with the genre. [27] The awkward combination of experimental tower defense mechanics with 3D graphics was not well received, but later titles refined its execution paving the way for a popular new breed of games. Dungeon Defenders , released in October 2010, was one of the first tower defense games to bring the genre to the third person perspective. It sold over 250,000 copies in first two weeks of release [28] and over 600,000 copies by the end of 2011. [29] The 2011 title Sanctum , and its 2013 sequel popularized the first person shooter hybrid that was pioneered by these earlier games. [30]

Anomaly: Warzone Earth released in 2011 introduced a variation of gameplay which has been described as "reverse tower defense", [31] "tower attack", [32] and "tower offense". [33] In the game, the player must attack the enemy bases protected by numerous defenses. Sequels and other games have since experimented further with both styles of tower defense. [34]

With the advent of social networking service applications, such as the Facebook Platform, tower defense has become a popular genre with titles such as Bloons TD and Plants vs. Zombies Adventures making the transition to turn-based play. [35]


A screenshot of Defenders of Ardania showing the genre's characteristic towers, as well as units and a castle that serves as an end point Defenders of Ardania 4.jpeg
A screenshot of Defenders of Ardania showing the genre's characteristic towers, as well as units and a castle that serves as an end point
Simple 1-bit tower defense game for Arduboy. Tower defense (micro td).gif
Simple 1-bit tower defense game for Arduboy.

The basic gameplay elements of tower defense are:

What distinguishes tower defense base defending games from other base defending games (such as Space Invaders, or other games where bases are defended) is the player's ability to strategically place, construct or summon obstructive constructions and constructive obstructions in the path of attacking enemies.

In a tower defense, unlike the base, the player's main character is often invincible, as the primary object is the survival of the base rather than the player.

Some features of modern tower defense:

Many modern tower defense games evolved from real-time to turn-based gameplay in which there is a cycle in which there are distinct phases such as build, defend, repair, and celebrate. Many games, such as Flash Element Tower Defense feature enemies that scamper through a "maze", which allows the player to strategically place "towers" for optimal effectiveness. [37] However, some versions of the genre force the user to create the "maze" out of their own "towers", such as Desktop Tower Defense . [38] Some versions of the genre are a hybrid of these two types, with preset paths that can be modified to some extent by tower placement, or towers that can be modified by path placement, or modifications that can be placed by tower paths. Often an essential strategy is "mazing", which is the tactic of creating a long, winding path of towers (or "maze") to lengthen the distance the enemies must traverse to get past the defense. Sometimes "juggling" is possible by alternating between barricading an exit on one side and then the other side to cause the enemies to path back and forth until they are defeated. Some games also allow players to modify the attack strategy used by towers to be able to defend for an even more tantalizingly reasonable price. [39]

The degree of the player's control (or lack thereof) in such games also varies from games where the player controls a unit within the game world, to games where the player has no direct control over units at all, or even no control over the game whatsoever.

It is a common theme in tower defense games to have "air" units which do not pass through the layout of the maze, but rather fly over the towers directly to the end destination.

Some tower defense games or custom maps also require the player to send out enemies to their opponents' game boards respectively their controlled areas at a common game board. Such games are also known as tower wars game boards.

USPTO trademark

On June 3, 2008, COM2US Corporation was awarded the trademark for the term "Tower Defense", filed on June 13, 2007 – serial number 3442002. The corporation is reported to have started enforcing the trademark: in early 2010, developers of games on Apple's App Store reported receiving messages requiring name changes for their games, citing trademark violation. [40] [41] Adding the phrase "Tower Defense" (in capital letters) to the description of an app submission to iTunesConnect and the app store automatically triggers a warning that the submission is likely to be rejected for use of the term; however, writing the phrase in lower case is still acceptable as "tower defense" is a valid description of a game style.

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Survival horror is a subgenre of video games inspired by horror fiction that focuses on survival of the character as the game tries to frighten players with either horror graphics or scary ambience. Although combat can be part of the gameplay, the player is made to feel less in control than in typical action games through limited ammunition, health, speed and vision, or through various obstructions of the player's interaction with the game mechanics. The player is also challenged to find items that unlock the path to new areas and solve puzzles to proceed in the game. Games make use of strong horror themes, like dark maze-like environments and unexpected attacks from enemies.

<i>Dungeon Siege</i> 2002 action role-playing video game

Dungeon Siege is an action role-playing video game developed by Gas Powered Games and published by Microsoft in April 2002, for Microsoft Windows, and the following year by Destineer for Mac OS X. Set in the pseudo-medieval kingdom of Ehb, the high fantasy game follows a young farmer and his companions as they journey to defeat an invading force. Initially only seeking to warn the nearby town of the invasion of a race of creatures named the Krug, the farmer and the companions that join him along the way are soon swept up in finding a way to defeat another race called the Seck, resurgent after being trapped for 300 years. Unlike other role-playing video games of the time, the world of Dungeon Siege does not have levels but is a single, continuous area without loading screens that the player journeys through, fighting hordes of enemies. Also, rather than setting character classes and manually controlling all of the characters in the group, the player controls their overall tactics and weapons and magic usage, which direct their character growth.

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<i>The Tower of Druaga</i> 1984 video game

The Tower of Druaga is a 1984 action role-playing maze arcade game developed and published in Japan by Namco. Controlling the golden-armored knight Gilgamesh, the player is tasked with scaling 60 floors of the titular tower in an effort to rescue the maiden Ki from Druaga, a four-armed demon who plans to use an artifact known as the Blue Crystal Rod to enslave all of mankind. It ran on the Namco Super Pac-Man arcade hardware, modified with a horizontal-scrolling video system used in Mappy.

<i>Dungeons & Dragons: Tower of Doom</i> 1994 video game

Dungeons & Dragons: Tower of Doom, published in 1994, is the first of two arcade games created by Capcom based on the Dungeons & Dragons tabletop role-playing game and set in the Mystara campaign setting. It is a side scrolling beat 'em up with some role-playing video game elements mixed in. The game was also released on the Sega Saturn, packaged with its sequel, Dungeons & Dragons: Shadow over Mystara, under the title Dungeons & Dragons Collection, although the Saturn version limited the gameplay to only two players. In 2013, both games were re-released for modern platforms as Dungeons & Dragons: Chronicles of Mystara.

<i>Incoming</i> (1998 video game) 1998 video game

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Beat 'em up is a video game genre featuring hand-to-hand combat between the protagonist and an improbably large number of opponents. Traditional beat 'em ups take place in scrolling, two-dimensional (2D) levels, though some later games feature more open three-dimensional (3D) environments with yet larger numbers of enemies. These games are noted for their simple gameplay, a source of both critical acclaim and derision. Two-player cooperative gameplay and multiple player characters are also hallmarks of the genre. Most of these games take place in urban settings and feature crime-fighting and revenge-based plots, though some games may employ historical, science fiction or fantasy themes.

Side-scrolling video game video game genre

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<i>Desktop Tower Defense</i> video game

Desktop Tower Defense is a Flash-based tower defense browser game created by Paul Preece in March 2007. The game had been played over 15.7 million times as of July 2007, and was one of Webware 100's top ten entertainment web applications of 2007. Desktop Tower Defense is available in an English, Spanish, German, French, or Italian interface. In May 2009, a commercial Nintendo DS version became available.

<i>Defense Grid: The Awakening</i> Tower defense video game first released in 2008

Defense Grid: The Awakening is a tower defense video game developed by Hidden Path Entertainment for Windows and Xbox Live Arcade on the Xbox 360. The game was one of the titles promoted by Microsoft during their Game Developers Conference keynote speech on February 20, 2008. The game was released for Microsoft Windows on December 8, 2008 and for Xbox 360 on September 2, 2009. The OS X version shipped from Virtual Programming on July 7, 2010.

<i>Crystal Defenders</i> video game

Crystal Defenders is a set of two tower defense video games developed and published by Square Enix. The games use the setting of Ivalice and design elements from Final Fantasy Tactics A2: Grimoire of the Rift, forming part of the wider Final Fantasy franchise. The games feature a selection of characters sporting Final Fantasy-based character classes, and play out tower defense scenarios against recurring series of monsters. The first game in the series is Crystal Guardians, which was released in three parts for Japanese mobile phones in 2008. It was adapted for iOS later that year as Square Enix's first game for the platform, and renamed to Crystal Defenders. Under that name, the game was also released between 2009 and 2011 for Android, Xbox Live Arcade, WiiWare, and PlayStation 3 and PlayStation Portable via the PlayStation Store. It was re-released with graphical improvements for iOS as Crystal Defenders Plus in 2013. A sequel, Crystal Defenders: Vanguard Storm, was released for iOS in 2009.

<i>Final Fantasy Crystal Chronicles: My Life as a Darklord</i> video game

Final Fantasy Crystal Chronicles: My Life as a Darklord is a tower defense video game developed and published by Square Enix for the Wii and distributed through the WiiWare download service. The game is part of the Final Fantasy Crystal Chronicles series.

<i>Bloons Tower Defense</i> Tower defense video game series featuring popping of enemy balloons

Bloons Tower Defense is a series of tower defense games under the Bloons series created and produced by Ninja Kiwi. The game was initially developed as a browser game, built upon the Adobe Flash platform and released in 2007. Later games in the series expanded to support various mobile platforms, including Android, iOS, Windows Phone, PlayStation Portable and Nintendo DSi.

<i>ProtoGalaxy</i> video game

ProtoGalaxy is a cross-genre video game for Microsoft Windows that was released on October 6, 2010. In the game's back-story, a species of powerful, unknown extraterrestrials enters the Milky Way with the intention of enslaving its inhabitants. The player characters must defend Earth from this alien threat and restore human civilization. ProtoGalaxy is a 2.5D game; the 2D playing field employs 3D graphics. ProtoGalaxy incorporates elements of a variety of gaming genres, such as adventure, arcade, shooter, puzzle, and role-playing genres.

<i>Dungeon Defenders</i> video game

Dungeon Defenders is a multiplayer video game developed by Trendy Entertainment that combines the genres of tower defense and action role-playing game. It is based on a showcase of Unreal Engine 3 named Dungeon Defense. The game takes place in a fantasy setting where players control the young apprentices of wizards and warriors and defend against hordes of monsters. Dungeon Defenders was announced on August 25, 2010, and has been released on Xbox Live Arcade, PlayStation Network and PC. Support for the Move accessory is planned for inclusion in the PlayStation Network version. Epic Games' Mark Rein has stated that there will be cross platform play between the PlayStation 3 and the PlayStation Vita. The game was released on October 19, 2011 through Steam. In November there was a "development kit" released as free DLC which included the game's source code.

Gem Tower Defense is a tower defense video game created by Bryan K. It was released on February 18, 2007 under the tower defense subsection of Blizzard's Warcraft III: The Frozen Throne minigames. Several game clients, Flash browser game websites and mobile devices have hosted variants of the game. The game is based upon strategy, mazing, decision making and chance. The goal of the game is to eliminate computer-controlled enemies that follow a set path to reach the end of a pathway. "Gems" are structures players build to defend their maze. Each Gem is randomly distributed leaving it to chance for a player to acquire the one needed. Gems are placed to form a maze for extending the length each enemy unit travels thereby increasing the attack time of the Gems. Both the type and quality of the Gems selected determine the damage and use of the structure.


  1. 1 2 3 "Best Tower Defense Games of All Time. Damon Reece. April 27, 2015 "Archived copy". Archived from the original on March 29, 2016. Retrieved March 29, 2016.CS1 maint: archived copy as title (link)
  2. Dugan, Patrick (January 30, 2007). "Slamdance, Post-Columbine – Personal Conversations with Freaks and Geeks". Gamasutra. Archived from the original on August 4, 2013.
  3. Remo, Chris; Sheffield, Brandon (July 11, 2008). "Interview: Soren Johnson – Spore's Strategist". Gamasutra. Archived from the original on October 14, 2012.
  4. 1 2 WHY WE LOVE TOWER DEFENSE Ryan Clements, IGN. 24 SEP 2012
  5. 1 2 The Creation of Missile Command and the haunting of its creator Dave Theurer. Alex Rubens. August 15, 2013. "Archived copy". Archived from the original on June 7, 2014. Retrieved June 12, 2014.CS1 maint: archived copy as title (link)
  6. Ellison, Harlan (September 1982). "Rolling That Ole Debbil Stone". Video Review . IPC Business Press. 3 (6). ISSN   0261-3263. (reprinted in The Comics Journal . No.85. Pg.108. October 1983. ISSN   0194-7869; later reprints in Ellison collections Sleepless Nights in the Procrustean Bed (1984) and An Edge in My Voice (1985)).
  7. van der Heide, Martijn. "Pedro". World of Spectrum. Archived from the original on June 6, 2011. Retrieved December 19, 2008.
  8. 1 2 3 Mitchell, Luke (June 22, 2008). "Tower Defense: Bringing the genre back". PALGN. Archived from the original on February 3, 2014. Retrieved December 24, 2008.
  9. 1 2 Matt Fox (January 3, 2013). The Video Games Guide: 1,000+ Arcade, Console and Computer Games, 1962-2012, 2d ed. McFarland. pp. 90–. ISBN   978-1-4766-0067-3.
  10. "Top 100 RPGs of All Time -". Archived from the original on March 4, 2018. Retrieved May 7, 2018.
  11. Meer, Alec (August 7, 2010). "Why Dungeon Keeper has never been beaten". PC Gamer. Retrieved May 16, 2016.
  12. Schneider, Peer (December 11, 1998). "Turok 2: Seeds of Evil".
  13. Walbridge, Michael (June 12, 2008). "Analysis: Defense of the Ancients – An Underground Revolution". GamaSutra. Archived from the original on May 21, 2013.
  14. Jay (January 11, 2007). "Flash Element TD". Jayisgames. Archived from the original on August 28, 2013.
  15. Cario, Erwan (November 10, 2007). "Jouer plus pour travailler moins Jeux vidéo. Sélection de petites douceurs en ligne, dangereusement addictives". Libération. Archived from the original on July 26, 2008.
  16. Remo, Chris (November 18, 2008). "Interview: Flash Tower Defense Creators On VC Deal, Social Gaming Site". Gamasutra. Archived from the original on October 15, 2012.
  17. Lemes, David (May 22, 2007). "Antbuster: Game Nacional Online". Game Reporter. Archived from the original on September 15, 2015.
  18. Valadares, Guilherme (June 5, 2007). "Antbuster, jogo brasileiro é premiado em disputa internacional - Papo de Homem". Papo de Homem. Archived from the original on December 31, 2007.
  19. "2008 IGF Awards Topped By Crayon Physics Deluxe". Gamasutra. February 21, 2008. Archived from the original on May 20, 2013.
  20. Roush, George (December 5, 2007). "Tower Defense Review". IGN. Archived from the original on March 30, 2012.
  21. W., Tim (June 13, 2008). "Best Of Indie Games: Rose, Camellia, Ziczac & Nameless". Gamasutra. Archived from the original on October 23, 2012.
  22. Hatfield, Daemon (September 22, 2008). "Ninjatown Multiplayer Hands-on". IGN. Archived from the original on October 21, 2012.
  23. "Kiwi games industry booms". Gameplanet. Archived from the original on February 1, 2014. Retrieved January 2, 2014.
  24. Kelly, Kevin (August 30, 2008). "PAX 2008 hands-on: Defense Grid: The Awakening". Joystiq . Weblogs. Archived from the original on October 28, 2012.
  25. "About GauntNet".
  26. Ambrozy, Brian (November 20, 2009). "Plants vs. Zombies nominated for PC Game of the Year". Icrontic. Icrontic. Archived from the original on August 13, 2012.
  27. Haynes, Jeff (April 2, 2009). "Iron Grip: Warlord Review". Archived from the original on January 12, 2018. Retrieved May 7, 2018.
  28. Andrews, Jason. "Dungeon Defenders Exceeds More than a Quarter of a Million in Sales". Internal News. Archived from the original on January 3, 2012. Retrieved September 9, 2013.
  29. Sliwinski, Alexander (December 22, 2011). "Dungeon Defenders picks up gold from 600K sales". Joystiq. Archived from the original on March 30, 2013. Retrieved August 17, 2013.
  30. Meunier, Nathan (May 4, 2013). "Sanctum 2 Merges First-Person Shooting and Tower Defense. Intriguing..." Archived from the original on January 11, 2018. Retrieved May 7, 2018.
  31. Patterson, Blake (March 22, 2011). "GDC 2011: Upcoming 'Anomaly Warzone Earth' – Tower Defense in Reverse". Touch Arcade. Archived from the original on March 26, 2011. Retrieved March 30, 2011.
  32. Cameron, Gordon (December 14, 2010). "Plugged In - Tower defense gets turned on its head in Anomaly: Warzone Earth". Yahoo! Games. Archived from the original on January 25, 2011. Retrieved April 9, 2011.
  33. Biessener, Adam (April 8, 2011). "Anomaly: Warzone Earth - Tower Offense Delivers Unusual Thrills". Game Informer. Archived from the original on April 15, 2011. Retrieved April 10, 2011.
  34. "Anomaly Defenders announced, reverses 'tower offense' gameplay". Archived from the original on August 2, 2017. Retrieved May 7, 2018.
  35. "Plants vs. Zombies Adventures Announced for Facebook". July 14, 2014. Archived from the original on September 27, 2016.
  36. Rutkoff, Aaron (June 20, 2007). "Strategy Game Pits Players Against Desktop Invasion". Wall Street Journal. Archived from the original on August 9, 2017. Retrieved August 31, 2013.
  37. Scott, David. "Flash Element Tower Defense". Archived from the original on April 14, 2009. Retrieved April 15, 2009.
  38. Preece, Paul. "Desktop Tower Defense". Archived from the original on July 10, 2009. Retrieved September 25, 2008.
  39. "CreepTD manual". Archived from the original on February 28, 2012. Retrieved February 13, 2012.
  40. Jordan, Jon (January 25, 2010). "Com2uS "guides" developers not to use its trademark Tower Defense". Archived from the original on May 30, 2013.
  41. Slashandburn/Mgate Labs (January 21, 2010). ""Tower Defense" is now up for CP Infringement". Touch Arcade. Archived from the original on May 18, 2015. Retrieved May 8, 2015.