When I heard about the supposed Downer Ending in Punch-Out!! Wii's "Mac's Last Stand", I didn't quite get it at first. Three defeats, and Mac simply retires. Then I saw the cutscene leading up to it, and then the ending scene. Then it clicked into my head. It was Mac's conscious decision. He's already become the world champion, and defended his title. He's already made his dream a reality. But he can't hold on to that title forever. Further along the line, there may be scandals, and perhaps a losing streak that will force him to retire anyway, going out with a whimper. So, he takes a third option - go out with a bang. And he makes his decision damn clear to Doc, who reluctantly goes along with it.
Doc Louis: Alright, kid. Let's go out on top. It's time to take your place in history.
- It's also a Homage to Little Mac's inspiration, the titular character of Ashita no Joe, who goes out in a similar way.