You can see how much the D&D image/brand changed in the space of only two years. Lost Tamoachan: The Hidden Shrine of Tamoachan was the bagged (unbound) tournament module used at Origins International Game Expo (known simply as ‘Origins’) in 1979. You’ll find the complete publication history at The Acaeum. (Copies are incredibly rare.) The cover art is by David C. Sutherland III, who did the original, and best, Dungeon Master’s Guide (1979) cover.
The module was renamed upon wide release in 1980, with front and back covers by Erol Otus. Without access to color, he relied on textures—the chiseled walls, the bolt of fire, the demon’s hair, the warrior’s armor. (On the back cover, it’s the combination of trees, ancient stone, translucent scales.) The Aztec art looks damn convincing, and the shadow of the wings on the walls is the kind of detail that separates Otus from other artists.
Otus did the front cover of the 1981 edition as well. Despite the gorgeous coloring and the thicker, more abstract figures that would become his trademark style, I think I prefer the earlier, more three-dimensional work. The back cover is by Jeff Dee. He uses Otus’s template for the scene, but gives it a Marvel Comics flavor. The innocence—some would argue the purity—of early D&D art, represented by the first and second editions of Tamoachan, would never be seen again.
Read some background on the module’s development at Wizards of the Coast.