SPACE INVADERS

• Mystery ship trick - By counting your shots, hitting the UFO with every 23rd shot yields the maximum 300 points.  Maximum numbers of UFOs for the first 3 screens are 8, 6, and 4.

• A different version of Space Invaders (with different graphics) apparently exists (pictures #1 and #2).  The top-row invaders actually resemble the “monster” graphics on the machine!  It’s believed that this version came from overseas either as an original release or a hack.

• Here is the ordered UFO score table. It is a circular list, and the pointer moves every time you fire:
100,050,050,100,150,100,100,050,300,100,100,100,050,150,100,050   {Eduardo Mello}

• BUG: If an invader is firing at the exact moment it’s moving down to row 2, it runs into its own missile. The game detects this as a missile collision. On all other rows, this would get ignored, but it turns out that later in the code when the missile subroutine runs, the only thing that is checked for a collision with the player's ship is the height of the missile. It does not bother to check if the X position lines up. It assumes that if an invader's missile hits something this low, it must be the player ship. So therefore a ship is killed even though it was not hit.  {Don Hodges}

• BUG: If you leave one of the “skull” invaders from the bottom-two rows as the last one to shoot, it will start leaving a trail of what sort of looks like exclamation points (picture #3).  This was later done intentionally (and expanded upon) in the sequel, Deluxe Space Invaders.

• BUG: The Taito and Midway schematics both have the sound circuitry for the invader hit and mystery ship/saucer/ufo hit labeling reversed.

• RUMOR: On the fifth wave of invaders, the second mystery ship will deflect your shot with the rarely heard "deflection shot" sound f/x - a shot sound played backwards.

• RUMOR: Back in 2000 in the RGVAC newsgroup (LINK), Brian Deuel claimed it was possible to shoot all of the invaders except the first two rows (the "skulls"), the invaders would stop marching, leaving you to endlessly shoot mystery saucers. He also claimed he did it and witnessed someone else do it as well, but both myself and someone else (VIDEO) using MAME and save states confirmed this wasn’t true.