superstarCSB, on Apr 23 2004, 02:32 PM, said:
I believe the version used on Nick Arcade may be the same version used at CES 1992 - this magazine scan, found on Sonic CulT, details the unveiling of Sonic 2 at CES and lists many similarities with the "Nick Arcade" version, such as Sonic 1 music.
This might explain why SEGA would have given Nick Arcade this version of the game - the show would have been filmed quite far in advance of its air date, so possibly the version used at CES would have been the only development copy they had that had been optimised for non-internal use (such as the disabling of Tails in 1-player mode when, from the videos, you can see him in the CPZ and EHZ demos - his coding was far from complete at that stage, as our much later prototype shows, so he would not have been fit for the media to see in action at that time).
It's interesting to note that although according to the magazine only one level (GHZ) was available for normal play in this version (as opposed to the four in our prototype), it was very far along in development - even at the early stage it was at, both level maps must have been completed enough to play through (though from the NA vids we can see they were quite different in places), and the boss was reportedly active aswell.
Just thought this was interesting to note, although it's not exactly relevant to the topic come to think of it. =/ If anyone thinks this is important enough / irrelevant enough to split off into it's own topic, be my guest.
EDIT: Linked to a mirror of the file, instead of the original. Check out CulT's Sonic 2 section if you really want to be nitpicky. ;P