Super Punch-Out has been hiding two secret codes for the last 28 years

gamesradar.com:

Classic Nintendo game Super Punch-Out has had two secret codes hidden within it that have gone largely unnoticed for the last 28 years.  

As shared by Twitter user @new_cheats_news (opens in new tab), the fighting game from 1994 is hiding a couple of cheat codes that not a lot of people know about. According to the tweet: "All secret codes in this game use two-button combinations. Two of them are known: Sound test and Japanese name input. But there are two more."

At the title, hold Y+R, then press A or START. Following screen will appear instead or regular menus. Here you can select any character to fight a free single match. See, even fighters from SPECIAL CIRCUIT are available here. -> pic.twitter.com/Hh7AtPdTcKAugust 8, 2022

The first find by 'Unlisted Cheats' allows players to select any character to fight in a free single match. According to the tweet, all you need to do to pull this off is hold Y and R, then press A or Start. Once you’ve done this, a new screen will appear instead of the regular menu which will allow you to select any character to fight in a free single match - apparently even fighters from Special Circuit are available to use. 

Further down in the thread by Unlisted Cheats, the second of the two new discoveries is revealed. Apparently, once you select one of the fighters on the screen mentioned above and are on the character info screen, hold B and Y and then A or Start again and you’ll be able to control the CPU opponent from JOYPAD2, meaning you can fight against a real-life player two and not a computer. Unlisted Cheats does however mention that "all combinations must be held on JOYPAD2, then A or Start on JOYPAD1."

Sorry! Completely forgot to mention! All combinations must be held on JOYPAD2!