In Bugs you must destroy the swarms of invading bugs, out to immobilize your space craft, before they completely leave their nests.
At the same time, you must be on constant guard against the Phylax oozing through the hull of your craft and bent on destroying your only weapon.
Using your paddle controller, position your Ultrasonic Weapon (the "aiming cursor" seen on your screen) directly below the emerging Bugs. You will see Ultrasonic Energy Packets leaving your ship's firing bays and moving toward the aiming cursor to destroy the Bug above. You must destroy the Bugs before they completely leave their nests or they will damage your ship.
While you are destroying Bugs, you must also watch for the Phylax-sent by the Super-Bugs to penetrate your ship's hull and destroy your weapon. As long as a Phylax is green he is outside your ship and harmless. Your weapon is also harmless to him. But when a Phylax changes color to yellow (a warning) and then red, he has entered your ship. You must try to destroy him, by luring him into your weapon's line of fire, before he makes contact with your weapon.
Here's how you rack up points:
Each bug destroyed scores one point.
Destroying a Phylax scores five points.
After you score thirty points you advance automatically to a new skill level (indicated by a new Cosmic Barrier), scoring a bonus of eight additional points.