Knuckles VS Metal Sonic
OK, so I took AmonBoxing (one of the example games). I replaced the photo with a drawing of Metal Sonic and I replaced the gloves with drawings of Knuckles's fists. Press the up and down arrow keys to box. Press the left and right arrow keys to move.
Metal Sonic and Knuckles are Sonic the Hedgehog characters, therefore they are copyright Sega and Sonic Team.
Original game by...Amon I guess.