'how destructive' is correct and usable in written English.
You can use it when you want to emphasize the destruction caused by something. For example: "The cyclone's impact was devastating; how destructive it was!".
"It's just amazing how destructive we're capable of being".
"How destructive banking reform is killing the economy --Jacket.
The first is the knowledge of just how destructive and catastrophic war can be.
"We can see for ourselves how destructive to our democracy this can become," he said.
From personal experience I know how destructive racial hatred can be.
"I wanted them to hear how destructive the sounds of their aircraft were," he said.
"Or perhaps she was the personification of how destructive and lost I was feeling".
And I saw how destructive the care system is for a lot of children.
Those references let the game indicate how destructive Guybrush has been.
For every hour it shreds, it needs an hour of maintenance, that's how destructive it is.
I cannot tell you how destructive that kind of thing is in a movie….
