Raster"The fifth quadrant", I played this with a pirated copy without a manual, that doesn't make really a difference because the manual says little or nothing about the game mechanics.
I would really liked try to finish it, but never fully managed to figure out the code system, and the manual itself doesn't give hints about how it works.
Commodore C64 - The Fifth Quadrant © 1987 Bubble Bus - Gameplay
DESCRIPTION The Fifth Quadrant is an Adventure game, developed and published by Bubble Bus, which was released in 1987.