No. Sonic Jam is itself a compilation, with a small overworld. It has yet to be released anywhere else but the Sega Saturn. The games in the compilation, however, have been released on many other compilations.
No, it isn't, since Sonic Jam itself was a collection, not an actual game.
You can`t.
you don't.
You can play it on the Sega Genesis, in Sonic Jam for the Sega Saturn, Sonic Mega Collection for the Gamecube, Sonic Mega Collection Plus for the PS2 and Xbox, Sonic the Hedgehog Genesis for Game Boy Advance, Sega Genesis Collection for PS2,and Sonic's Ultimate Genesis Collection for PS3 and Xbox 360
A Gem of a Jam was created in 1943.
Sonic Jam happened in 1997.
You can't use Lock-on technology like you could with Sonic Jam, however the lock-on technology created games can be unlocked by starting several games for set number of times. Which games and how many times - this depends on your platform.
A Gem of a Jam - 1943 was released on: USA: 30 December 1943
It is not on Sonic Mega Collection but it is on Sonic Gems Collection.
Sonic Jam was created on 1997-06-20.
The rainbow gem is an incomplete gem that's supposed to let you transform into super sonic but it doesn't work. You can only get it by hacking.
Sonic Mega Collection Plus is the same as Sonic Mega Collection except with additional unlockables.