James "Buster" Douglas Knockout Boxing (Mega Drive)/Hidden content
From Sega Retro
Sound test
On the main screen, press 
+ START on controller two[1].
Continue
Press 
and 
on the Game Over screen. This is valid only once for the same opponent[1].
Play as the same character in 2-player versus mode
After the first player as chosen their character, hold START while choosing with 
or 
. You should be able to see and select the first player's character.
References
