You look lovely/beautiful is correct. "You play lovely" is not.
One can look or sound good (adjective) because the verbs look and sound are just variants of is that describe the state of someone or something. Play on the other hand is a definite action, and so absolutely requires an adverb. You play well, not "play good". A car runs well, not "runs good" -- although, to be fair, "runs good" is an extremely common illiteracy when talking about cars.
[By the way, please be careful with the forms "are" and "is", and whenever saying them think whether they refer to one thing or to several. Likewise nouns and adjectives. Are those sentences correct? or Is that sentence correct?, not the way you put it. Also I hope you can help me.]
Student or Learner