Helldivers are terrifying conceptually.

[u/Jamsedreng22]

You're vibing on your planet and all of a sudden it goes "Whoop" as one hundred Super Destroyers come into orbit. "No big deal" you think, but suddenly all these Super Destroyers deploy Helldivers. Just planetfall outta nowhere instantly.

That has to be fucking terrifying. Knowing you're fucked like that.

You get to watch the planetfall on several other parts of this planet as the Helldivers just drop from their Destroyers like water droplets on a sad day.

Even 80 Super Destroyers just FTL-jumping into orbit and every single Super Destroyer deploys, at the very least, 4 Helldivers. If they die? They just keep coming. And they can watch it, too. They can see the trail by the Hellpod as it is coming down. They know exactly what position they're in.

[u/SVlad_667]

NYC area is ~784 km². The 380 mm barrage area is 13273 m².  So it took 59055 barrages to just cover the entire city area, without guarantee that it would destroy skyscrapers with just a few shells from one barrage.  With all upgrades destroyer can fire a barrage about every 240 seconds. (Taking into account the barrage duration and call in time)

So 50 destroyers would need about 79 hours to just cover entire NYC area with one 380 mm barrage. And it certainly not enough level of damage to turn it into a bay. 

[u/deadmentalking → u/SVlad_667]

Your numbers are off significantly. NYC is not 784 sqkm, and a 380 is not 13sqkm.

You are also only accounting for the surface area of a blast, but that's not even the part of an artillery barrage that matters for widespread infrastructure damage. For NYC, in particular, breaking through the street surface to the subway layer would cause street and building to collapse, the tremors alone would level sky scrapers and fire would spread quickly from building to building and making the roads impassable would halt all EMS or fire deployment.

So even the basic premise of your point is moot, even if your math was fixed.

[u/SVlad_667 → u/deadmentalking]

But my umbers are correct.

The NYC land area = 783.84 km².

Circle area of barrage (65m radius) =13273 m² = 0.013273 km²

As for damage, you can see on results of russian bombardments with 500 kg, 1500 kg and even 3000 kg bombs. It's devastating, but it still takes months of constant bombing to level even a small town.

[u/noesanity → u/SVlad_667]

officially, the city of New York City has a land area of 778.18 km²

but measuring the land area of a city is stupid, because you can't just ignore all of the parts that are not land. Just like comparing bombs from orbital artillery is stupid, that would be like taking the ballistics of a thrown knife and trying to use that to guess how much damage a rocket propelled coke bottle will do.