Catalogue of Arcade Emulation Software - the Absolute Reference

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Defender (Red label)

Defender (c) 12/1980 Williams.

Defender is a legendary, side-scrolling shoot-em-up. The player is charged with the mission of protecting a group of humanoids, stranded on an alien planet, from alien abductors. The game's levels are occupied by a large number of 'lander' aliens that try to abduct the humanoids from the planet's surface and take them to the top of the play area. If it succeeds, the lander and captured humanoid will merge into an alien 'mutant'. If a lander is destroyed after it has captured a humanoid but before it mutates, the humanoid is released and falls towards the ground; it must be caught by the player and returned to the planet's surface before it falls to its death. If all of the humanoids are abducted or otherwise killed, the entire planet is destroyed and all of the landers change into mutants.

The challenge becomes more intense as the levels progress, with 'bomber' enemies dropping mines, and 'pods' which break into many 'swarmers', which also must be destroyed. If the player does not finish the level fast enough, the extremely dangerous 'baiter' enemy will emerge and attack. The player's ship is equipped with a laser and a limited number of 'smart bombs' (although their power is limited). There is also a 'hyperspace' function which transports the player's ship to a random location, but sometimes the ship is destroyed upon rematerialization. An on-screen scanner aids the player by showing the location of all humanoids and alien enemies in relation to the current position of the player's ship.


Board Number : D75 (top), D71F (A)

Prom Stickers : DF

Main CPU : M6809 (@ 1 Mhz)

Sound CPU : M6808 (@ 894.75 Khz)

Sound Chips : DAC

Screen orientation : Horizontal

Video resolution : 294 x 239 pixels

Screen refresh : 60.00 Hz

Palette colors : 16

Players : 2

Control : 2-way joystick (vertical)

Buttons : 5



Along with Namco's seminal "Pac-Man", Defender shares the title of 'Highest Grossing Video Game of All Time' and to date has earned more than one billion dollars. It's interesting to note that when the now-legendary shoot-em-up was first shown at a 1981 Chicago arcade machine trade show, it was deemed to be a flop due to its high level of difficulty. Arcade industry insiders confidently predicted that both Defender and "Pac-Man" would be commercial flops and that Namco's "Rally X" would be the next major arcade success.

Defender's attract mode for the game was programmed in just five hours.

Defender was noted for both its superb sound and visual effects and, moreover, for its extremely demanding gameplay. This didn't, however, stop players from accumulating millions of points when playing the game. Just minutes after the opening of the AMOA - an arcade industry trade show - Eugene Jarvis and his team - Defender's creators - were burning new ROMs for the game's display due to the fact they plugged the first burn into the board BACKWARDS and fried them. Due to the intimidating controls, hardly anyone at the show played the game and there were even rumours circulating suggesting that both "Pac-Man" and Defender would flop and that Namco's "Rally X" would be the next big hit. Not only did Defender have the highest number of controls (five buttons, in addition to a two-way joystick) but it was also the first video game to feature an artificial 'world', in that game events occured OUTSIDE the on-screen viewing area presented to the player.

Chris Hoffman holds the official record for this game on 'Marathon' settings with 79,976,975 points on January 1, 1984.

Gino Yoo holds the official record for this game on 'Tournament' settings with 230,125 points.

Some bootlegs of this game are known as "Star Trek 1981", "Defence Command", "Defense Command", "Zero" (Jeutel), and "Tornado" (Jeutel).

Defender inspired a catchy hit song by Buckner and Garcia called 'Defender' released on the 'Pac-Man Fever' album.

A Defender unit appears in the 1983 movie 'Terms of Endearment', in the 1983 movie 'Joysticks' and in the 1983 movie 'Koyaanisqatsi - Life out of Balance'.

Three Defender machines (including one cocktail) were shown at the 2003 classic arcade games show 'California Extreme' in San Jose, California.

MB (Milton Bradley) released a boardgame based on this video game (same name) in 1983 : win the most points by using your Defender ships to protect Humanoids from waves of aliens. A set of chance cards will bring the different aliens (bombers, landers and Humanoids) into play. Movement is determined with a spinner. Players can move their defenders and aliens.


Defender ROM sets were distinguished by early and later editions. The early edition supported only upright cabinets. In 1981 Williams released a cocktail cabinet version which necessitated extra code to flip the video display and to support a second set of game controls. The editions had some minor differences in the game's attract mode : The early edition gave an erroneous point value of '100' for alien landers; this was corrected to '150' in the later edition. Also, the high score value for player PGD was '14185' in the early edition and '14285' in the later edition.

Early edition ROM sets :

* Defender (White Label)

* Defender (Green Label)

Later edition ROM sets :

* Defender (Red Label)


Lander : 150 points.

Mutant : 150 points.

Baiter : 200 points.

Bomber : 250 points.

Pod : 1000 points.

Swarmer : 150 points.

Saving a humanoid from a Lander : 500 points.

Depositing a humanoid into the ground : 500 points.

Humanoid landing into the ground safely on his own : 250 points.

Bonus at the end of each wave :

Wave 1 : Humanoids Left X 100.

Wave 2 : Humanoids Left X 200.

Wave 3 : Humanoids Left X 300.

Wave 4 : Humanoids Left X 400.

Wave 5 and above : Humanoids Left X 500.


* Avoid using hyperspace unless you are about to die. Fighting off attacks, regardless of the number of enemies, will make you a better Defender player.

* Baiters can usually be overcome by hitting the reverse button twice quickly. They will fly past you and be in range for your fire power. Do NOT try to outrun them as baiters are faster than your ship.

* Swarmers are easy to defeat. You can hit reverse as soon as they fly past you and fly behind them. They cannot shoot backwards so you can blast away at will.

* At higher levels, you will need to play God and even sacrifice some humanoids (by killing them yourself) to preserve the rest of the planet's population. The planet is too large for you protect and you are sparing the humanoids from a fate worst than death (mutation). Do not worry, these humanoids reproduce quickly and overpopulation has always been a constant problem. The planet will be fully populated at the start of every fifth attack wave (configurable).

* The International Date Line : there are reverse lines for swarmers and mutants (AKA the 'International Date Line'). If this line is between you and the type of enemy in question, they will travel the opposite direction around the planet to get you (i.e. they won't cross this line to get to you). If a mutant, say, is following you and you cross the mutant reverse line (to the left of the big mountain) it will suddenly reverse direction and go around the other way. The same is true for the swarmer reverse line (located approximately where your ship starts each wave). This doesn't affect swarmers that you are following behind. If you're on one side of the line and a pod is on the other and you shoot it open, the swarmers will fly away from you and you can get in behind them immediately. The best use of these lines is where there are lots of swarmers and/or mutants that you don't want to hassle with. You stay near the line and go back and forth over it to keep the enemy on the other side of the planet. This is especially useful in space and waves that get really hairy.

* Freeze : you can freeze a Defender machine by picking up all ten humanoids (on any wave, but Wave 1 is your greatest chance at success), stopping all forward motion of your ship, quieting the screen down (i.e. having no enemies moving around on it) and setting all the humanoids straight down quickly. This seems to work better were the terrain is very close to the bottom of the screen. Everything will freeze, but you can still move your ship up and down. Thrusting will break the spell, so to speak. If you do pick a spot with shallow terrain, some humanoids will go thru the bottom of the screen and appear suspended in mid-air near the top. This trick is good to use during marathon games when you've reached Wave 256 and need a breather.

* Some top players begin each round by shooting all the humanoids except for one, which they pick up. The planet is too large for you protect and you are sparing the humanoids from mutation, a fate worse than death. This keeps mutants from developing, but it also means that the planet explodes if you lose your last humanoid. The planet is fully repopulated at the start of every fifth attack wave (configurable). This can be considered an advanced trick.

* This trick is to win 100+ ships between 990,000 and 1,000,000, thus fooling the game based on where score rolls over rather than where ships roll over. The version where you win 100+ ships has been tested, the version where you win 256+ ships never was because :

a) For every scoring activity from 990,000 to 999,975 you will win one extra ship and one extra smart bomb.

b) If you suicide on something, including a shot but not including hyperspace (because dying from hyperspace awards no points), you will lose one ship, but also gain one (net effect on ships is zero) plus one smart bomb.

c) For winning n ships from 990,000 to 999,975, including suicides, you will have to achieve n x 10,000 points after passing 1,000,000 before the game's accounting balances and ships are awarded properly at 10,000 point intervals again. The score returns to zero every 1,000,000, meaning that if you had won 100 ships, the machine would have to wait 1,000,000 points to begin awarding ships again. However, since 1,000,000 is equivalent to zero it awards them immediately at 1,010,000. -- or --

d) Being an 8-bit game, 255 ships is the maximum recognized. 256 ships or smart bombs are treated as zero. If you win exactly 256 ships during this period, the machine will think you have won none and thus begin awarding ships immediately at 1,010,000.

e) In either case, you get to keep your surplus ships and bombs and can have super long turns where you bomb 2 to 3 times per wave to get out of dangerous situations.

* It's possible on a real Defender machine to make the screen color inverted so that all the black space is white while you are playing. It will reset itself when you die and maybe when you use hyperspace. Smart bomb flashes are cool when it's reversed. The trick was to drop a credit in right when you die and the screen flashes white. Somehow the program gets distracted (non masked interrupt on coin drop?) and the screen stays white.

* Defender attack waves 'roll over' at wave 100, which is displayed, after being completed, as wave 0. The game keeps track of the actual number of waves, even though they are not shown properly. For example, the next wave will be counted as wave 101, even though it shows being completed as wave 1. The game will 'roll over' again at wave 200, which is displayed, after being completed, as wave 0 as well.


1. Defender (1980)

2. Stargate (1981)

3. Strikeforce (1991)

4. Defender 2000 (1996, Atari Jaguar)


Staff : Eugene Jarvis (DRJ), Sam Dicker (SAM), Larry DeMar (LED), Paul Dussault (PGD), (CRB), Mike Stroll (MRS), Steve Ritchie (SSR), (TMH)


* Consoles :

Atari 2600 (1981)

Atari 5200 (1982)

Entex AdventureVision (1982)

Emerson Arcadia (1982, "Space Squadron")

Atari XEGS

Colecovision (1983)

Mattel Intellivision (1983)

Nintendo Game Boy (1995, "Defender / Joust")

Nintendo Super Famicom (1996, "Williams Arcade's Greatest Hits")

Sega Mega Drive (1996, "Williams Arcade's Greatest Hits")

Atari Jaguar (1996, "Defender 2000")

Sega Saturn (1996, "Williams Arcade's Greatest Hits")

Sony PlayStation (1996, "Williams Arcade's Greatest Hits")

Nintendo Game Boy Color (1998, "Arcade Hits - Defender / Joust")

Nintendo 64 (2000, "Midway's Greatest Arcade Hits Volume I")

Sega Dreamcast (2000, "Midway's Greatest Arcade Hits Vol. 1")

Nintendo Game Boy Advance (2001, "Midway's Greatest Arcade Hits")

Nintendo Game Boy Advance (2002)

Sony PlayStation 2 (2003, "Midway Arcade Treasure")

Nintendo GameCube (2003, "Midway Arcade Treasure")

Microsoft XBOX (2003, "Midway Arcade Treasure")

Sony PSP (2005, "Midway Arcade Treasures - Extended Play")

* Computers :

Tandy Color Computer (1982, "Starfire")

Tandy Color Computer (1982, "Planet Invasion")

Tandy Color Computer (1982, "Offender")

Atari 800 (1982)

TI99/4a (1983)

Commodore C64 (1983)

PC [Booter] (1983)

Apple II (1983)

Commodore VIC-20 (1983)

BBC B (1983, "Super Defender" - Acornsoft)

ZX Spectrum (1990, "Guardian II" - Hi-Tech Software Ltd 'UK')

Atari ST (1990, "Defender II" - ARC developments, Atari UK, limited)

Commodore Amiga (1990, "Defender II" - ARC developments, Atari UK, limited)

Commodore Amiga (1991, "Zeron"- Acid software)

Commodore Amiga (1994, "Defender" - Shareware)

PC [MS-DOS] (1995, "Williams Arcade Classics")

PC [MS Windows] (1996, "Williams Arcade Classics")

PC [MS Windows, CD-ROM] (2004, "Midway Arcade Treasure")

Microtan 65

* Others :

VFD handheld game (1982) released by Entex.

VFD handheld game (19??) released by Gakken : the screen is a little smaller than the Entex version.

Palm OS ("Midway Arcade Classic")

Tiger Game.Com ("Arcade Classics")


F.A.Q. by Kevin Butler A.K.A. War Doc