Super Mario Bros. (TechEruo's Unreleased Commodore 64 port)

Development
The game was cancelled because Nintendo of Eruowood thought it was better than the iconic NES port, and would decrease sales of said port. It was however finished and leaked online in 2008 by one of the main developers.

Differences From the NES version

 * Due to the C64's limitations, only half the colors from the original game's palette were used.

Colors
The game utilizes all 16 of the Commodore 64's colors at least once.

Black

 * Bullet Bill
 * Buzzy Beetle (Shell)
 * Night Backdrop

White

 * 1Up Mushroom (Bottom)
 * Clouds
 * Fire Mario/Luigi (Shirt)
 * Snow
 * Super Mushroom (Bottom)

Red

 * Fire Bar
 * Fire Luigi (Overalls & hat)
 * Lava
 * Mario (Overalls & hat)
 * Piranha Plant (Fireball)
 * Super Mushroom (Spots)

Cyan

 * 1Up Mushroom (Top)
 * "Transparent" Water

Violet

 * Peach's Dress

Green

 * Bowser (Shell)
 * Koopa Troopa (Shell)
 * Trees/Bushes

Blue

 * Underground Blocks

Yellow

 * Bowser (Skin)
 * Coins
 * Koopa Troopa (Skin)

Orange

 * Bowser (Flame)
 * Fire Flower (Top)
 * Fire Mario/Luigi (fireball)
 * Goomba (Legs)
 * Super Mushroom (Top)

Brown

 * Castle Axe
 * Goomba (Skin)

Light Red

 * Fire Mario (Overalls & hat)

Dark Grey

 * Goomba (Castle palette)
 * Koopa Troopa (Shell, castle palette)

Medium Grey

 * Castle Walls

Light Green

 * 1Up Mushroom (Spots)
 * Fire Flower (Stem)
 * Luigi (Overalls & hat)

Light Blue

 * Overworld Backdrop

Light Grey

 * Bowser (Shell spikes)
 * Pipes (Castle palette)