impacted/puerile polish

[Vladv1]

"In this hotspot, the Bay Area’s favorite denim-clad devils go about their business thrashing the daylights inside and out of the new extreme metal, recasting it as something one is able to process and make pleasurable; the thrash is compacted, impacted, punky but crafted to a puerile polish by the quick right hand of Hetfield. Martin Popoff "500 best hevy metal records"
What does the adjectives "impacted mean" here? https://www.merriam-webster.com/dictionary/impacted It doesn't have the meaning I am lookin for in this dictionary. And what does "puerile polish" mean here?

 

[Tarheel]

The music world does, in a sense, have its own language. (Some would question whether heavy metal is music.)

 

[Skrej]

"In this hotspot, the Bay Area’s favorite denim-clad devils go about their business thrashing the daylights inside and out of the new extreme metal, recasting it as something one is able to process and make pleasurable; the thrash is compacted, impacted, punky but crafted to a puerile polish by the quick right hand of Hetfield. Martin Popoff "500 best hevy metal records"
What does the adjectives "impacted mean" here? https://www.merriam-webster.com/dictionary/impacted It doesn't have the meaning I am lookin for in this dictionary. And what does "puerile polish" mean here?

See definition #2 of the dictionary link you included.

Look up the individual meanings of puerile and polish (noun, note the lowercase), and combine them.