"It reflects badly" is a complete sentence. "It" is the subject, "reflects" is the verb, "badly" is acting as a predicate adjective modifying the pronoun it. The entire sentence itself is modifying the sentence that came before that one.
The sentence is not the most lengthy, but it is complete.
Yes, but the sentence is extremely unclear.
The pronoun “It” is a poorly chosen subject. But more important, there is no object. “It” reflects badly of who or what?