A nice chap released a IPS patch for Super Mario Land 2: Six Golden Coins for Gameboy that adds full color.
If you're unfamilure, download the following files:
1) Super Mario Land 2 - 6 Golden Coins (UE) (V1.2) [!].zip
2) SML2DX.zip
3) lips102.zip (Lunar patcher)
You can then launch Lunar, select the original SM2 ROM and patch it. Viola, a full color version!
Something nice to fire up the RPi for tomorrow :) Article here:
https://goo.gl/TA7WbU
--- ENiGMA 1/2 v0.0.8-alpha (linux; x64; 6.11.3)
* Origin: Xibalba -+- xibalba.l33t.codes:44510 (80:774/20)