The Open Space Theater Experiment is giving an unpretentiously straightforward revival of Henrik Ibsen's mystic but fascinating last play. The seldom-performed ''When We Dead Awaken,'' with its autobiographical allusions, continues Ibsen's troubled probings of such themes as the betrayal of idealism, the subtly corrupting effects of fame and material success, and the relative importance of life and art in human experience. Through the mysterious Irene (Kim Hunter), his ardent protagonist, Ibsen votes for life. But it is a life beyond the mundane existence most worldlings endure or enjoy. It is a sense of life achieved, as the play's title states, ''When We Dead Awaken.''
The play opens at a Norwegian coastal spa as Arnold Rubek (Tom Klunis) and his considerably younger wife, Maja (Anne Toomey), begin facing up to the unfulfilled promises of a marriage that began, for Rubek, on the rebound. Like Ibsen himself, the sculptor has returned to Norway after many years of self-exile. A coolly embittered Maja chides Rubek for failing in his pledge to take her with him to the top of a high mountain and show her ''all the glory of the world.''
Instead, it appears that since completing ''The Day of Resurrection,'' the masterwork that made him famous, Rubek has settled for being a popular, well-paid portraitist, making masks over what he sees as the bestial faces of men. Enter Irene, the model for ''Resurrection,'' whose reaction to the sculptor's apparent casual disregard of their inspired collaboration led to a period of madness. In subsequent conversations at a mountain health resort and the jagged mountainside above it, the degree of Rubek's betrayal and the depth of Irene's tragedy become apparent. Maja meanwhile has found freedom and consolation in the earthy company of Ulfhejm (Nicholas Wyman), a voracious bear hunter, a thoroughly macho male whose best friends are his hounds.
The challenge of ''When We Dead Awaken'' is to handle its extravagant imaginings, symbolism, and lyric passages in a manner that grasps their magnitude without making them seem grandiose for audiences of a more literal-minded age. The revival staged by Stephen Zuckerman, aided by James Fenhagen's abstractly modest setting, manages the feat with considerable adroitness and clarity.
In the activating role of Irene, Miss Hunter conveys the regained composure of a woman whose self-dedication to Rubek's artistic achievement led to years of self-debasement and destructive relationships. In her looks and expressiveness, Miss Hunter realizes the tragic beauty and eloquence of the intensely poised Irene. What she lacks is a certain enigmatic elusiveness.
Mr. Klunis's Rubek, the artist as fame-achiever, registers both the restiveness and remorse of a man whose betrayals became evident with his first success. Miss Toomey plays the jilted but consolable Maja with a light touch and a certain gallant resiliency. Mr. Wyman swaggers amusingly as the virile Norse huntsman. Ken Costigan bows and scrapes as the health spa manager, and Dana Cameron Keeler makes a silent, shadowy figure of Irene's attendant nun.
Understandably, the children, guests, waiters, and hunting hounds described in Ibsen's stage directions remain offstage at the Open Space. Mr. Fenhagen suggests the play's locales with inclined ramps. A bolt of blue cloth serves as a mountain stream. Richard Winkler's atmospheric lighting works for the most part satisfactorily, but the multicolored sunburst projection used to suggest the snow avalanche that engulfs Rubek and Irene scarcely approximates the apocalyptic finale. The costumes are by Carol H. Beule, and Dan Erkkila has composed some crystalline incidental music to match the mountain airs.