April 27, 1995
In Astal's game code a sprite of a character looking alsmost exactly like Mario can be found trough hacking, but it's unused in the actual game. It's unknown if it's a character scrapped from the game during development, or if it was used as early test graphics. It's also possible to be created as an easter egg as it is.
Note that he's depicted with blue shirt and red overalls, like in Mario's first appearances, and has no gloves.
Astal's company Sega had no right over Nintendo's character Mario, and this may be the reason for the sprite not being included in the actual game.