Also known as: Space War (JP), Space Laser (EU)
Two spaceships fire lasers at each other and innocent aliens get caught in the crossfire. Who's the real Intruder, huh???
There are two chunks of source code in the main CPU. The first is at 0x0028:
9280 CNAKA EOU 1558H
The second is at 0x13C6 and corresponds to code at 0x035E to 0x0365 in the main CPU:
1656 SHLD 21A4H 1660 LHLD 21A2H 1664 MOV A,M 1668 S
There are three sets in MAME: spcewarl (Space War), spclaser (Space Laser), and intruder (...Intruder). spclaser and intruder are meant for upright arcade cabinets, and spcewarl is for a cocktail table.
There's evidence of a cocktail table version of Space Laser, though as of this writing that set has yet to be dumped.
Space War has an extra screen in attract mode with Leijac's logo and telephone number. The screen is actually in all versions of the game, but Intruder and Space Laser dummy it out. Put the following cheat in MAME's intruder.xml / spclaser.xml cheat files to re-enable the Leijac screen:
<cheat desc="Enable Leijac Screen"> <script state="run"> <action>maincpu.mb@18D3=08</action> <action>maincpu.mb@19D8=01</action> </script> <script state="off"> <action>maincpu.mb@18D3=00</action> <action>maincpu.mb@19D8=00</action> </script> </cheat>
Konami's version is called Space War, Taito's version is Space Laser, and Game Plan's version is Intruder.
The cocktail versions (like spcewarl) have support for 1 or 2 players, while the upright versions (spcwar and intruder) are 1-player only. The code to support Player 2 is in all versions, and MAME even has 2-player support for these sets, but the actual upright cabinet only had one joystick and one fire button.
Space War prints information for Player 1 and Player 2 upside-down on the bottom of the screen, since it's for a cocktail table and all. The upright versions delete Player 2's information and replaces the text at the bottom of the screen with a "floor", the game's name, and the publisher info. Note that Taito Corp is credited even in the Game Plan version.