NOTE: I know there is another topic about this, but its patch does not work. This patch runs on a Sonic 2 rom of the SMD filetype, NOT the Sonic 2K rom. This had people in the inactive topic confused. The patch contains a hack which basically builds S2K the "hard way", implementing Knuckles and his features by modding S2 code with S2K code containing Knuckles' moves. Because it's not a "lock-on" and is fully independent from SK besides Knuckles' moves taken from SK, it does not create a large ROM and therefore is playable. Tested and works. LINK: http://www.mediafire.com/?y98tk5z9zxvxedn Enjoy!