What is the name of the sonic game for Sega where you need Sonic 2 to be put into it

The name of the game is Sonic and Knuckles.
Incept from wikipedia. http://en.wikipedia.org/wiki/Sonic_&_Knuckles
The lock-on technology was actually a way of making up for the fact that the developers could not meet the deadline for Sonic 3. Originally, Sonic 3 was to be released with Knuckles as a playable character, and with all the Sonic & Knuckles levels playable (the level select screen in Sonic 3 features inaccessible Sonic & Knuckleslevels and music for said levels can be played in the sound test). Time constraints forced them to split the project in two, releasing Sonic 3with the completed levels and continuing work on the uncompleted ones, plus adding the Super Emeralds, and the lock-on gimmick. Indeed Sonic 2 had once run into similar problems, resulting in the original Hidden Palace and several other levels being removed.