Sonic 3 and Blue Knuckles is a ROM hack of Sonic 3 and Knuckles. It adds in Blue Knuckles, a 'hidden' character in the original Sonic 3 and Knuckles, which he was only playable through glitches or hacking. This hack is also adding a new zone, currently in the works.
A new zone (partly)
Screenshots & Videos
The unedited title screen.
http://shc.sonicresearch.org/Image/e57i2|640|480|672|The unedited title screen.
Blue Knuckles is not amused.
http://shc.sonicresearch.org/Image/e57i3|640|480|672|Blue Knuckles is not amused.
Blue Knuckles vs Angel Island Miniboss.
http://shc.sonicresearch.org/Image/e57i4|640|480|672|Blue Knuckles vs Angel Island Miniboss.