Wait for it...
What really staggers me is how little boom there is for the bombs' size. They're bigger than some cities, yet the explosions they make are barely big enough to destroy their own mass, if that.
I mean, obviously, they're weapons of intimidation rather than anything else. "Look how much we can waste throwing at you, you guys, you're so [insert crass adjectival verb]."
(This is from the apparently ongoing Space Battleship Yamato remake. Space Battleship Yamato is known in the US as "Star Blazers.")