Me and my friend had the idea to get 100% in old games we used to love. Both him and me, when playing Rayman2, had the same glitch:
In the Echoing Caves fase, after getting to one certain check-point, it says "Please insert CD". You can see that one of the bridges is missing, and the barrel keeps respawning and falling into nothingness. We both own our own original games, and we don't take the CD off at any moment. So far there has been no answer to this glitch online.