Battle Vader is a clone of the Space Invaders arcade hit from Taito, but adapted to the limited features of the Cassette Vision system. Thus only the front row of the invaders is visible, surely to limit de number of moving objects to display.
Your bunkers has to be shot three times before they are definately destroyed. Each time an invader hit one, it changes color according to the following cycle: red -> yellow -> blue.
Coming soon...
Coming soon...
Coming soon...