seriously vs badly

seriously and badly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
seriously	No	No	No	Yes
badly	No	No	No	Yes

As adverbs, seriously and badly are synonyms defined as:

Other synonyms of seriously include gravely, severely.

seriously (adverb)	badly (adverb)
in a serious manner	(`ill' is often used as a combining form) in a poor or improper or unsatisfactory manner; not well
to a severe or serious degree	to a severe or serious degree
	very much; strongly
	with great intensity (`bad' is a nonstandard variant for `badly')
	in a disobedient or naughty way
	evilly or wickedly
	unfavorably or with disapproval
	with unusual distress or resentment or regret or emotional display
	in a disadvantageous way; to someone's disadvantage
	without skill or in a displeasing manner