If any single criticism were to be leveled against Joseph Walker's The River Niger … it might be that it contains too much. But that is a good fault—one that in this case is both an aspect of the play's exuberance and integral to its purpose. The River Niger depicts the morass of Harlem; it heaps together vitality, corruption, agony, aspiration, violence and a will to transcendence. No salient trait predominates, except ferment, a ferment of existence struggling confusedly and valiantly to transfigure itself into coherence. The play's statement is humorous, lyric, virile, crude, and oddly inspiring….

[The] play is somewhat untidy in construction and spills over into melodrama. These are blemishes, but they do not impair the pulse of truth and human energy that keep the play constantly engaging. Through its rough naturalism there runs a vein of authentic poetry of feeling and speech. The play has something naively "romantic" about it and, though overwritten, is theatrically enlivening and emotionally stirring….

Johnny (and the author) feel themselves rooted in an age-old soil of African cosmology, a monistic sense of the unity of man and nature, flesh and spirit, humanity as a single tribe…. Whether Johnny's poem is good or not is less to the point than that its essential meaning informs the play and gives it a dimension beyond the local color of its realism.