Space Invaders II (c) 03/1980 Midway.
Space Invaders II allowed for 2-Player simultaneous competitive play (although both players could work together). Besides shooting the invaders, one of the goals was to destroy your opponent (either CPU or another player) and gain his ships!

>>> TECHNICAL DETAILS
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Game ID : 851
Main CPU : 8080 (@ 1.9968 Mhz)
Sound Chips : (2x) Samples, (2x) SN76477 (@ 1.9968 Mhz)
Screen orientation : Vertical
Video resolution : 224 x 256 pixels
Screen refresh : 60.00 Hz
Palette colors : 2
Players : 2
Control : 2-way joystick
Buttons : 1

>>> TRIVIA
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This game was a Midway in-house project, done by Joel Kreger. His name can be found in one of the game ROMs using a hex editor. This game runs on modified SI Deluxe hardware, with two sound boards; one for each player. Player 2's sound was a bit higher in pitch than player 1. The sounds of player 2 are also a bit different, with the enemy explosion and ship destroyed sounds being different than player 1. The overlay contained many colors, running from red (player 1) to yellow (player 2), with various shades of blue and green in between.
The game used a Z80A processor. Replacing the CPU with a regular Z80 causes the game to play the 'THUMP THUMP' sound during the attract mode.

>>> TRICKS AND TIPS
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Occasionally, a mystery ship will fly by, dropping more invaders!! When 2 players are playing, TWO different mystery ships fly by. The points for shooting them range from 50 pts to 525 pts (!!!).
When playing with 2 players, player-2 has lost all of his ships, and he still has invaders left on his side, they will move back and forth when they 'land' endlessly, until player 1 destroys them.
If 2 players are playing, player-2 has lost all of his ships, and player-1 clears player-2's board with ships left, player-2 will gain one of player 1's ships to return to the game!!

>>> DESIGNERS / PROGRAMMERS / STAFF
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Designed & programmed by : Joel Kreger

>>> OTHER GAME RESOURCES
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Game's rom.