SDI: Strategic Defense Initiative

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(Redirected from Global Defense)

SDI title.png
SDI: Strategic Defense Initiative
Publisher: Sega, Commodore Amiga Amstrad CPC Atari ST Commodore 64 ZX Spectrum Activision
System(s): Sega System 16, Sega Master System, Amiga, Amstrad CPC, Atari ST, Commodore 64, ZX Spectrum
ROM size: Sega Master System 128kB
Genre: Shoot-'em-Up

Number of players: 2
Release Date RRP Code
Arcade World 1987  ?
Sega Master System JP 1987-10-24 ¥5,000 G-1338
Sega Master System US 1988-03 $40.00 [1]Media:CGW US 050.pdf  ?
Sega Master System EU 1988-03 £22.95 [2]Media:ACE UK 16.pdf MK-5102-50
Sega Master System KR 19xx ₩? GB-1338
Commodore Amiga UK 1988 £24.99  ?
Atari ST UK 1988 £19.99  ?
Amstrad CPC UK (cassette) 1988 £9.99  ?
Amstrad CPC UK (disk) 1988 £14.99  ?
Amstrad CPC UK (The Hit Squad) 19xx £2.99  ?
Amstrad CPC ES (cassette) 19xx  ?Ptas  ?
Commodore 64 US (cartridge) 1988 $?  ?
Commodore 64 UK (cassette) 1988 £14.99  ?
Commodore 64 UK (disk) 1988 £14.99  ?
Commodore 64 UK (The Hit Squad) 19xx £2.99  ?
ZX Spectrum UK (cassette) 1988 £9.99 URK 301
ZX Spectrum UK (The Hit Squad) 19xx £2.99  ?
ZX Spectrum ES (cassette) 19xx  ?Ptas SEC 576

SDI: Strategic Defense Initiative is a 1987 shoot-'em-up arcade game developed by Sega for the Sega System 16 arcade platform.


Unusual for its time, SDI has the player assume the role of a satellite, tasked with destroying enemy satellites and missiles. Each level is divided into two "modes" - "offensive" mode, which takes the form of a sidescrolling shoot-'em-up, and "defensive" mode which is built more similarly to Atari's Missile Command. Beating both modes allows the player to progress, however, if the player can destroy all the enemies in offensive mode, defensive mode does not take place.

SDI not only gives the player control over the movement of the satellite, but also its aim. This mechanic was implemented in the original arcade cabinet through the form of a joystick and trackball - the joystick moving the player, the trackball moving the crosshair. On the top of the joystick is a button for firing.

A perfect game of SDI will result in the satellite being replaced with Flicky.


SDI was ported to the Sega Master System in 1987/1988, where western versions were renamed Global Defense. The Master System version, as well as cutting back on the graphical and audio quality, has to vastly reduce the difficulty of the game to match up with a new control scheme - as the console lacks a trackball, the player needs to switch between moving and aiming during play (holding 1 while moving the D-Pad allows the satellite to move, otherwise the D-Pad only controls the crosshair). This makes moving and aiming at the same time impossible. However, the U.S. manual lists an alternate two-controller configuration in which the first controller aims and the second controller moves the satellite. When the game is started in this configuration, the satellite fires automatically. To start the game with two controllers, on the second controller either press Left and 1 or Right and 2.

Activision brought the game to home computers in Europe - the Amiga, Amstrad CPC, Atari ST, Commodore 64 and ZX Spectrum (not to be confused with S.D.I., an unrelated game also released for the Amiga and Atari ST).

These days, SDI is often grouped with another arcade game from the era, Quartet. Both were released as part of Volume 21 of the Sega Ages 2500 series, Sega Ages 2500 Series Vol. 21: SDI & Quartet: Sega System 16 Collection for the PlayStation 2. SDI & Quartet: Original Soundtrack contains the official soundtrack of both games.

Production Credits

Arcade Version

Planed by: Black Holl Tomo
Project Leader: Joe Kacchan
Programer: Sweet Tohchan, Anatano Pideshi, Ippo Ogapi
Character Design: Saitama Kenji, 8940 Kon
Scene Design: Henchan
Music by: Funky Gerogero
Sound Effects: Nao Chan
Mechanical Engineer: MI.U.I.Hachi
Enemy Creation: Demon Taka
Data Adjust: Nanno Icchan
Special Thanks: Mina Inochi, Hakusyon Daimaohe, Mamiko Chan, Uso Happyaku
Special No Thanks: Ashidematoi People
Presented by: Sega, Chin_Chin Brothers

(According to Sega Ages 2500 Vol. 21, Masaki Kondo (近藤 正樹) was a "Designer", Katsumi Tojo (藤乗 勝巳) was the "main programmer" and Eishi Kawatake (川竹 英士) was also a programmer. All three worked on Galaxy Force too).

Commodore 64 Version

(C)1988 Activision
Software Studios
Produced by Neil Jackson
Coding Graphics and Music was Produced by Source the Software House Ltd
Artwork by Bryn Redman, Ross Harris
Music Composed by Paul Summers
Programming by Mike Chilton

Promotional Material

Physical Scans

System 16 Version

System 16, JP

Master System version

Sega Master System 77 Sega Retro Average 
Based on 8 reviews
Publication Score Source
62 №14, p49Media:ACE UK 14.pdf
79 №1, p57
80 №4, p97
80 №78, p122/123
81 №5, p43
78 №8, p12Media:StheSegaMagazine_UK_08.pdf
80 №23, p57
78 №3, p19Media:Segapro UK 03.pdf
Master System, US
GlobalDefense SMS US Box.jpg
GlobalDefense SMS US Cart.jpg
Globaldefense sms us manual.pdf
SegaAdventure SMS US Poster Back.jpgSegaAdventure SMS US Poster Front.jpg
Master System, EU
SDI SMS EU cover.jpg
Master System, EU
"no limits" variant
SDI SMS EU nolimits cover.jpg
Master System, EU
® variant
SDI SMS EU R cover.jpg
Master System, JP
SDI SMS JP Box Back.jpgSDI SMS JP Box Spine.jpgSDI SMS JP cover.jpg
SDI SMS JP Cart.jpg
Master System, AU

GlobalDefense SMS AU Cart.jpg
Master System, KR

SDI SMS KR cart.jpg

Amiga Version

Commodore Amiga 57 Sega Retro Average 
Based on 1 review
Publication Score Source
57 №22, p91
Amiga, UK

Amstrad CPC Version

Amstrad CPC 54 Sega Retro Average 
Based on 2 reviews
Publication Score Source
79 №20, p78Media:ACE UK 20.pdf
29 №18, p43
Amstrad CPC, UK

Amstrad CPC, UK
(The Hit Squad)
Amstrad CPC, ES

Atari ST Version

Atari ST 74 Sega Retro Average 
Based on 3 reviews
Publication Score Source
84 №15, p75Media:ACE UK 15.pdf
81 №86
56 №14, p81
Atari ST, UK

Commodore 64 Version

Commodore 64 61 Sega Retro Average 
Based on 3 reviews
Publication Score Source
54 №116
72 №118
56 №18, p43
Amiga, UK (cassette)

Amiga, UK (disk)

Commodore 64, UK
(The Hit Squad)
SDI C64 EU Box THS.jpg

ZX Spectrum Version

ZX Spectrum 48 Sega Retro Average 
Based on 2 reviews
Publication Score Source
59 №116
37 №18, p43
ZX Spectrum, UK
SDI Spectrum EU Inlay.jpg
ZX Spectrum, UK
(The Hit Squad)
SDI Spectrum EU Box THS.jpg
ZX Spectrum, ES
SDI Spectrum ES Box MCM.jpg