To completely beat a video game. This term was first used for arcade games that did one of two things:
1) After reaching a certain score it would reset back to zero. For instance, a game might only be able to keep track of 9999999 points. Getting one more point after this would "flip" the score to zero.
2) After beating the last level, the game continues but on the first level. A good example of this is Mario Bros.
This meaning of flip was eventually expanded to include games that had formal endings.
A coin in the battle mode of "Super Mario All-Stars", a video game for the Super Nintendo Entertainment System. Inspired by the quote from the movie "Jerry Maguire", "Some players have coin, but I have the quan."