Move with the mouse or WASD or arrow keys.
Your guns fire automatically.
Activate your shockwave using the mouse button or M or Z keys.
Pause with the SPACE bar.
Obliterate enemy alien spaceships as they attack in ever greater numbers.
Use your shockwave to disintegrate enemy photon bullets, block their laser beams and inflict more damage on their spaceships.
You can't reuse your shockwave until the blue power bar in the bottom right corner replenishes.
Collect bonuses ejected from dying ships:
coins - $10 + 5 poins
diamonds - $100 + 25 points
blue - 100 points
green - 500 points
orange - increment score multiplier
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.
Those evil aliens are at it again, invading our little corner of the galaxy once more, trying to conquer the Earth, enslave all mankind and in a word, whatnot.
Will they never learn that here on Earth we have an endless supply of fighter jocks with the right stuff to trash their entire armada from a single man spacecraft?
Oh well, I suppose you'd better get out there and show them who's the boss...