To introduce its second season of experimental plays, the New Theatre Workshop has presented two "established" works, in order to arouse interest in its later student-written productions. The Twelve Pound Look, by J. M. Barrie, forms a delightful one-act entree. But it precedes a main dish that is not so tempting, for Sean O'Casey's Shadow of a Gunman is a confusing play. The chief trouble with this presentation is its selection in the first place. The acting, however, in both these productions is skillful.

Barrie's play is typically charming. As a vehicle for his irony, he depicted a situation in which an eminently self-satisfied gentleman and knight-elect hires a woman to type up replies to congratulatory letters. She turns out to be his former wife. Richard Smithies plays the pompous Sir Harry, in a loud and brusque manner quite suitable to the part. His secretary Kate is acted by Jo Linch in a style appropriately different from Sir Harry's. She is not animated, but placidly content--almost too serious; yet her benign laughter at him makes her restraint very convincing.

Clare Scott plays Sir Harry's new, brow-beaten wife with a fluttering meekness exactly appropriate. The real tribute to Glenn Goldberg's direction, however, is that Sir Harry and his secretary set each other off so well, both in word and in gesture.

Shadow of a Gunman is less successful. To be fully effective, O'Casey's play demands a studied performance, with its various parts considerably underplayed in order to achieve perspective and continuity. None of the actors in the New Theatre Workshop's presentation even attempted such an approach. If director Dean Gitter had tried to stifle their buoyancy, he would have overcome one weakness in the production. But it is the play, more than the acting, that is inadequate. Taken as a whole, the story is confusing, at times almost wild. Heavy Irish brogues hardly improve the clarity. Instead of being unified, therefore, Shadow of a Gunman emerges as a series of scenes in which various characters portray themselves.

Colgate Salsbury is wholly professional in the part of a red-pajama'd Irish salesman. His every grumble is funny. As a radical young poet, Woodruff Price seems to have a harder role. Perhaps this is because he plays it with less ease, though still effectively, as does Lee Jeffries in the role of the poet's lover, who sacrifices herself for him. An indignant landlord, John Ratte, sheds humor on the whole scene with his belligerent fist-shakings. Ann Adams and, again, Clare Scott, depict two sympathetic but gossipy old women in the boarding house where a detective, Bruce Fearing, is searching for conspirators.

Along with Rufus Marsh, Gitter himself rounds out the list of tenants in the cast. One good directing touch comes in the last scene, when he has the poet turn his back to the audience in despair. Shadow of a Gunman may not warrant a wildly enthusiastic audience this afternoon and evening, but it certainly deserves a critical one.