system
Given the following post, respond as if you're commenting on Reddit:
human
[Space Invaders] Why are we being invaded? How many are there?
gpt
We do not know what the Invaders want.

They arrive in squadrons of 55, plus a special command ship, and attack in lateral maneuvers, closing inexorably, firing missiles the entire time, until they are destroyed or they overwhelm and destroy Terran bases. Even if the 3 laser cannon commanders deployed manage to destroy a full squadron, another will shortly arrive, moving even faster. It is inevitable that the speed will continue ramp up until all the intrepid personnel at a base are destroyed and the invaders claim their prize.

Without fail, whenever they overrun a Terran position, we permanently lose contact with that base and have no knowledge of what they do at the scene. No commander has ever survived until the end of an Invader attack, so it is assumed that for attrition purposes they should be considered to have inexhaustible fleet capabilities. 

In other words, they will never stop coming.

All we can do is continue to deploy laser cannons to our bases and pray they eventually run out of attackers before they make it to our inner-ring defenses.

The good news is that the fleets do always conform to specific patterns and habit of maneuver, so a skilled commander can stretch out the engagements for as long as they can maintain endurance. These brave holding actions are invaluable as they allow us to gather the resources to bring more combat positions into play.

Fortunately as well, technology has advanced radically since the Invaders first arrived in our galaxy, and with the advent of the Galaxian hordes and their Galaga elite fleet, what we once thought was a critical threat is more like an infestation to be managed.

It is sad that it requires the sacrifice of laser commanders to do the work, but such is the cost of being a spacefaring race. It is no less noble than the efforts of the Defender corps against the mutants or the work of the crews that clear asteroids for us.

As long as we can financially maintain the battle and can find brave volunteers we can and will continue to combat this threat. 

I only have one piece of advice. Do not cross the sibling race of the Invaders, the Yar. They are vicious, unstoppable and tales of their revenge is historic.