After digging through a box of gifted LEGO for hours and only one piece of the instruction booklet left, I finally completed this. 6894 Blacktron Invader : r/lego
6894 - Back A - Back of the Box Builds
LEGO 6894 Blacktron Invader | BrickEconomy
Just bought 156 little pieces of my childhood! Lego BLACKTRON Invader 6894 : r/lego
LEGO Space Blacktron 6894 Invader 100% Complete | eBay