Gridrunner

Devilishly fast arcade game not unlike Centipede. You control a combat ship, the Gridrunner. Above you are the Gridsearch squads, caterpillar types who run in a line across each level of the grid and quickly descend to the next. If you knock off the caterpillar units one at a time and in order, you’re OK, but if you split them in the middle, they become little independent units of destruction and are harder to destroy. There are also the X and Y Zappers who run across the bottom of the grid. The X zappers usually harmless, but the Y zapper fires a deadly energy beam.
Your objectives: Clear the grid of the Gridsearch Squads – or die trying.