Answer:
"Somewhat loudly" and "poorly" are adverbs.
Explanation:
Wikipedia really explains adverbs beautifully, "an adverb is a word or an expression that modifies a verb, adjective, another adverb, determiner, clause, preposition, or sentence. Adverbs typically express manner, place, time, frequency, degree, level of certainty, etc., answering questions such as how?, in what way?, when?, where?, and to what extent?."
In what way did Bruce snore? "Somewhat loudly."
To what extent did Bruce sleep? "Poorly."
I hope this helps!