спектакль - spectacle - the performance in the theatre. пьеса - play, genre of literature. by this works of art people make spectacles. драма - drama, genre of play and of movie(mostly realistic films about life of ordinary people) , has several meanings. оказываться-оказаться - turn out to be(there is not real difference in the english language because it has not category of view) оказываться - что делать? - the continuous action оказаться - что сделать? - the perfect action. казаться - to seem -показаться - to show oneself, to appear, to seem as well and it has several translations in english

спектакль　пьеса　драма -they are similar kind of literature. спектакль - spectacle - perfomed in the theatre. пьеса - play - is a kind of literature work. And drama is opposite to comedy. You can watch drama on TV, but you can't watch play on TV. казаться-показаться - it depends on the context. казаться you can transtlate as It seemed to me - мне казалось, позазаться - is the same meaning as чудится but it is uesd in teh morden language more widely.