The evil aliens are invading our little corner of the galaxy once more, trying to conquer Earth. Use your shockwave to disintegrate enemy photon bullets, block their laser beams and inflict more damage on alien spaceships. The shockwave is available when the blue power bar in the bottom right corner replenishes. Your score multiplier applies to all points awarded for destroying enemies and collecing bonuses up until the end of the level. Spend accumulated money buying upgrades between levels.