Complex sentence: Sneaking onto a set, he attracts the attention of a young casting director, Gloria Brent (Ann Blyth) who recognizes his talent, although demonstration of his type of physical comedy for director Kurt Bergner (Peter Lorre) does not impress.
Split into simpler sentences: Sneaking onto a set, he attracts the attention of a young casting director, Gloria Brent (Ann Blyth). He demonstrates his type of physical comedy for director Kurt Bergner (Peter Lorre), whom he does not impress.