This is another arcade version of Wonder Boy, likely a slightly different revision or release than Set 3. Variations between sets could include minor graphical changes, bug fixes, or different ROM versions.  Gameplay would remain largely consistent with the core Wonder Boy experience: side-scrolling platforming, enemy encounters, and the quest to rescue Wonder Boy's girlfriend.

Wonder Boy (set 4, 315-5162)

Wonder Boy (set 2, 315-5178)