great racing game!!
The new charcaters you can unlock are mostly robot versions of existing charaters. and super sonic ( a yellow / gold version of sonic that goes faster than anyone else).
You can also get chos emeralds which unlock levels. if you get them all you get a bonus level that looks all flahing and rainbow coloured. and its more fast paced that the other levels.
Sonic R is a good game but not the best fro sonic fans.