Knuckles in Sonic 2 (prototype 0606)

From Sonic Retro

Fast Facts on Knuckles in Sonic 2 (prototype 0606)

Publisher: Sega Developer: Sonic Team System(s): Sega Mega Drive/Genesis

Knuckles in Sonic 2 prototype 0606 for the Sega Mega Drive/Genesis was released by drx during the February 23rd, 2008 proto release.

This prototype, along with every available build after the 0524 prototype, is a dump of the Sonic & Knuckles UPMEM chip. In order for this build to be playable, it must be attached to the beginning of a Sonic 2 ROM. Merging these two ROMs emulates the use of Lock-On Technology. The Knuckles in Sonic 2 0524 prototype is the only prototype released as a working stand-alone build.

DOWNLOAD
There are multiple downloads available for Knuckles in Sonic 2 (prototype 0606):

Original ROM (137KB).
Mounted for use on emulators (1.89MB).

Various Differences

Level Select is not enabled by default. At the title screen, pressing , , , , , and then + Start will enable it.
This is the first version to use the "Knuckles the Echinda" banner on the title screen.