R2

'R2 is a reference to what may be a missing level from Sonic CD. When examining the level files on the CD there is a list of levels and it skips from R1 (level 1) to R3 (level 3) with no R2. Also when using the Stage Select code it goes from levels 1 to 3, also leaving out 2. There are many speculations as to what it might have been. Some say the Desert level was to have been here, when it was taken out of Sonic 2, while others think it was the ruins level seen in an uncut pencil sketch. Although many topics have been started about this, most have led to arguments and usually only end up in frustration. All that is known about R2 is that it was originally the second stage, between Palmtree Panic and Collision Chaos.