Throughout its history, Moonlit Cove has been cited as representative of Ryder's mature period. Early critics discerned a mood of romantic mystery combined with faithful rendering of natural forms, which Ryder attained through continual exploration of light, particularly nocturnal effects. The painting's presence in the 1913 Armory Show highlighted its status as an icon for the American modernists. By 1916, when Phillips published his own article on Ryder, he viewed this painting as "one of the world's great romantic pictures." Intrigued by its narrative suggestion, he found a "luxury of danger" in the shadows of the empty boat and looming cliff. In After its purchase in 1924, he characterized it as "one of the greatest...of all Ryder's marines and landscapes".
Vestiges of an Ryder's earlier style—crisp silhouettes and flatly contoured forms—remain in Moonlit Cove, but it also shows a new conception in its thin, matte paint application and an austere composition reduced to a few powerfully arranged organic forms. The contours of the moored boat and the dark mass of the cliff and sky are arranged in a rhythm whose carefully measured intervals create a tight, interlocking structure, yet its simplicity suggests a random depiction of a scene found in nature. The image culminates in the halo of the moon within a sinuous cloud illuminating the cliff's contour. These spare elements suggest a spiritual presence.
The painting's condition reflects Ryder's eccentric experimentation with materials and methods. Due to the copious amounts of oil he applied to the back of the canvas, considerable darkening has occurred, and there is overall crazing, particularly in the sky and the water.