Retirement, or Game Over (in Punch-Out!!), is a certain scene, contributing to the player retiring from boxing, and usually happens after being defeated a couple of times, or either losing three times in Mac's Last Stand (or losing all three bouts).
In the original game of Punch-Out!!, players must get through the whole arcade game by defeating all opponents in a single match. If this streak is stopped, then a game over happens. No continues are available, which makes the game even harder.
Mike Tyson's Punch-Out!! Edit
If the player loses three times in any circuit (much like Mac's Last Stand, only nothing is affected), then this is counted as a Game Over. The player will then need to restart the whole game again.
Punch-Out!! (Wii) Edit
Unlike the original Punch-Out!! and it's NES counterpart, losing any amount of times in Contender or Title Defence does not cause Little Mac to retire. Instead, if the player loses three matches in Mac's Last Stand, then he will retire. Retiring is technically the only true end to the game, as Mac's Last Stand will continue forever until the player loses three times. In this game, once Mac retires, Career mode on that profile is locked off, meaning if the player did not unlock Donkey Kong or Champion's Mode during Mac's Last Stand, they are locked off to them forever, forcing them to start the game again on a new profile if they wish to unlock them.