Wonder Dog , a Sega Mega CD action & adventure game, follows the story of Wonder Dog, a canine with super jumping ability and throwing stars, as he tries to return home to Planet K-9. His journey begins when K-9 scientists send him to Earth as a pup to escape an impending invasion from the Pitbully Armada. Now, armed with the wonder serum, Wonder Dog must fight his way back to liberate K-9.
The gameplay involves side-scrolling platforming, with Wonder Dog able to jump high and throw stars at enemies. The game features various colorful stages, several hidden bonus rounds, and a large boss character at the end of nearly every level. Players will need to use Wonder Dog's abilities wisely to progress through the levels and ultimately defeat the final boss.