For three reasons, I want to commend to you "Woza Albert!," the South African political satire and fantasy that opened last night in Arena Stage's Kreeger Theater.

Two of them are Percy Mtwa and Mbongeni Ngema, who make up the Theater entire cast, although they essay so many quick-change roles in the course of the play's 90 intermissionless minutes that you may suspect they have a backup company of 30.

The third reason has to do with the play itself, which tackles such harsh realities as injustice, poverty and apartheid in South Africa, but does so with far more spirit, humor and, yes, hope, than the subject generally inspires. "Woza Albert!" may be a paean to the leaders who have died in the struggle for the liberation of South Africa's black population. But for all its polemics, it never relinquishes its claims to entertainment.

I've also got a reservation about the show, but the good things first.

In "Woza Albert!," Mtwa and Ngema, and their director Barney Simon, are imagining what might happen if a certain Morena, otherwise known as Jesus Christ, were to pick South Africa as the site for His second coming, arriving on a jumbo jet, no less, from Jersualem. He'd probably provoke some incredulity among the populace. The downtrodden would no doubt besiege him with demands for more food, the chance to work and an end to the nefarious passbook, which every black must carry, as if he were a stranger traveling in a strange land. Someone might even ask Him for a nice, new indoor barbershop. And an overworked laborer in a brickyard might logically wonder why, if He can multiply fishes and loaves, He can't also make bricks rain down from heaven.

The white authorities would certainly view His presence with alarm, brand Him a terrorist, or worse, a Communist, and hustle Him away to various prisons. He being who He is, though, He could float effortlessly out of barred windows or escape from even such a high-security facility as Robben Island by walking on the icy Atlantic waters that gird it. Whereupon the government might well bring out the planes and, in an attempt to blast Him off the planet, bomb Cape Town instead.

All this -- and considerably more -- does, in fact, happen on the stage of the Kreeger, which has been emptied of all props except for a trunk or two and a rack of costumes. And you'll see it unfold in extraordinary detail. Mtwa and Ngema are master pantomimists and gifted clowns, admirably adept at supplying their own sound effects, which range from the whirl of a helicopter's blade to the clickety-clack of a train hurtling along the tracks. With only their wonderful, wide-eyed talent, they can summon up a landscape, a society, a history. By putting little pink rubber balls on their noses, they even become those smug white folk, who make and enforce the ludicrous laws governing their country.

That said, I also feel obliged to pass on my reservation. For all the cleverness that attends its execution and for all the right-thinking stances it takes, the play is so far outdistanced by the players as to leave the text flopping in the dust. The script was apparently generated through improvisations by the actors and the director, an approach similar to that followed by South African actors Winston Ntshona and John Kani and playwright Athol Fugard, when they forged the stunning "Sizwe Banzi is Dead" and "The Island."

The difference, however, is that Fugard is a playwright (maybe the world's best right now), and that he molded and fixed what was most pertinent in his actors' improvisations. No one connected with "Woza Albert!" seems to have his rigorous eye. As a result, the play has a loose, sketchy quality and a fair number of its brief scenes beg off with a limp joke or a flat observation.

Part of the delight of "Woza Albert!" are the little diversions it takes -- showing us, for example, a toothless, palsied old codger attempting to thread a needle, or a barber shearing a customer, who could be a ram facing slaughter. By the same token, the diversions can be just that -- intrusions on the play's forward motion, robbing it of its theatrical drive. The actors, clad in sweat pants, expend a week's worth of energy on their multiple roles, but paradoxically "Woza Albert!" often gives the impression it is dawdling on its mad, merry way to the graveyard.

The final scene, you see, takes place in a cemetery, where Morena, invisible up to this point, suddenly appears to work His great miracle. ("I always come back after three days," He observes, "bombs or no bombs.") There, one by one, he resurrects from their tombs various martyrs and victims of the fight for civil rights in South Africa, starting with Albert Luthuli, the Zulu chief who won the Nobel Peace Prize in 1960.

"Woza" means "rise up" in the Sotho language. But the mounting refrain is less a cry of militancy than an affirmation of the rights of everyone to the abundance of life. Any play about apartheid has every cause to be embittered and angry. Mtwa and Ngema, ebullient actors both, make "Woza Albert!" a tribute to joy. Above all, the joy of performing.

WOZA ALBERT! Created by Barney Simon, Percy Mtwa and Mbongeni Ngema. Direction and set by Barney Simon; lighting, Mannie Manim. With Percy Mtwa and Mbongeni Ngema. At Arena's Kreeger Theater through Oct. 7.