I completed this game with S ranks everywere just yesterday, and yes, I found a lot of glitches.
Most glithes were about camera angle, sometimes they was about going through the ground and die (Green Hill, City Escape, Chemical Plant) and I got stuck into an invisible room twice, the first time in Planet Wisp classic, there is a wall where you can go above the level with the spike wisp but then you will be unable to escape; the second time was during the Egg Dragoon battle, I got stuck during a walljump section, the boss escaped but the invisible room trapped me forever.
In one of the City Escape missions (if I remember well, it was the one with classic sonic where you have to reach the goal in time and the level is full of big rotating wheels), I had a random teleport glitch
I think I found some more minor glitches other than these I listed above.
The game is still good, the glitches were not game breaking lilke some I found in the adventure game and Heroes (I've still not played '06), all what you have to do in this cases is pause and restart the level.