Your objective, as a member of the Planetary Liberation Force is
to travel to a series of alien worlds, freeing them from the
darkness that has beset them.
At the outset of each level, the world you must free is shown
briefly before it is blacked out. Take careful note of this, as
you will not get another look at the entire level until it is
completed. By travelling over the square sectors that make up
each chequered world you can illuminate it. When all the squares
have been illuminated, the exit square for that level flashes and
must be reached before the time limit expires to teleport to the
next world. Counters at the bottom of the screen display time
remaining and how many squares still need to be revealed to
complete the level.
To make things more difficult, some squares are 'dead ends' and
unlit squares beyond cannot be reached unless an alternative
route is found. Another problem is represented by the marauding
aliens that patrol each level intent on destroying your work.
While patrolling each planet they black out the squares you have
uncovered, making it necessary for you to return and uncover it
again before the level can be completed. If you come into contact
with an enemy a life is lost. Similarly, if you become trapped
on a 'dead end' square, your only alternative is to commit
suicide. As the game progresses, more alien enemies are
introduced and the hidden paths for each level become more
difficult to negotiate. Points are awarded for revealing squares,
with a bonus given upon the completion of each level, and
additional points awarded for time remaining.