His sense of drama, command over language, knowledge of dance and music and insight into human psychology enabled him to present the story of Nala and Damayanti in a compact form, observing auchitya to the maximum extent possible. He also sticks to the concept of a dominant rasa supported by other dependent rasas. The dramatic unravelling of the ups and downs in the career of a noble king and his beloved consort is magnificently achieved by Warrier. Variety in situation and characterization are provided by the introduction of characters like Kali, Pushkara, Rituparna, Karkotaka, Kattala and even the Hamsam (Swan). Even minor characters are presented as fulfledged human beings. Nalacharitham is the highwatermark of Kathakali literature mainly because of its profound human interest. The central plot is concerned with the fall of a noble and good man brought about by his accidental involvement in a game of dice and by the intervention of evil forces like Kali. He is rescued in the end, by his steadfastness and adherence to moral values. The heroine is unconsciously responsible for the jealousy of Kali, but at the end it is her goodness and her intelligence that come to the king's aid. King Nala and his queen, Damayanti, have become immortal characters, illustrating, through their suffereings the vicissitudes of human fortunes.
Among the many special features of Nalacharitam, is the happy blending of poetry, abhinaya (acting) and nritya (dance). One of the most felicitous passages from this point of view is the scene between Damayanti and the Swan-messanger. The cleverness of the Swan in drawing Damayanti away from her maids is superb dramatic material. He follows it up with an equally clever way of revealing his identity to her. Once her curiosity is aroused, it is easy for the Swan to find out how much she is interested in Nala. With his encouragement, unsuspected by her, she tells him about her love for Nala. On getting confirmation of it, the Swan proceeds to Kundinam to take the good news to King Nala. In the third day's play we have a touching soliloquy by Nala, now separated from his wife, sleepless in his grief, in the saddest moment of his life:

Unnayi Warrier seems to have been influenced by the pattern of classical drama in Sanskrit. This has helped him to tighten the structure, stead of leaving it loosely held together as in most attakkathas. The introduction of Narada as a kind of celestial Sutradhara to control and direct the course of the play provides a meaningful framework to the whole structure. His poetic gift has encouraged him to take freedom in the use of language. With the same boldness he has kept out as far as possible the merely conventional passages, often found in attakkathas but irrelevant to plot and character. Nalacharitam has an organic unity rarely found in attakkathas. Of all the writers of attakkathas Unnayi Warrier alone seems to have had the totality of his work in perspective; most of the others concentrated on the details and forgot about the whole. He was also more serious-minded than the others since there is a basically moral outlook controlling and underscoring the destinies of the characters presented by him. He must have meditated deeply on the presence of evil in the world and has tried to account for it in the course of his work.