Some old video games hold onto their secrets for many years and Super Punch-Out!! is one such game. One user has discovered a secret code for the 1994 Super NES game that unlocks a previously unknown multiplayer mode.
Even more, in this free match mode, at character info screen hold B+Y then press A or START. From now the CPU opponent can be controlled from JOYPAD2 so you can fight against a real person.
— Unlisted Cheats (@new_cheats_news) August 8, 2022
Unlisted Cheats on Twitter described their process in finding the game’s secret two-player mode. By holding down Y and R (on the second controller) and then pressing Start or A (on the first controller), users will be greeted a special screen as seen in the tweet. From there, holding B and Y (on the second controller) and pressing Start or A again (on the first controller) will let the player change the A.I. opponent into someone a second player can control.
Some chimed in in the replies, saying it worked on emulators, the version on Nintendo Switch Online, and the SNES Classic Edition, as well as the SNES original. As noted by Video Games Chronicle, the feature was likely implemented for testing purposes in order to save time.
This is not the first time someone has discovered something in the Punch-Out!! series after the fact. In 2016, YouTuber midwesternhousewives discovered a small visual trick that helps players know when to hit their opponent in Mike Tyson’s Punch-Out!!.
YouTuber zallard1 uploaded a video of the Super Punch-Out!! multiplayer mode in action, too. It shows what the buttons do for the other characters.