Originally, during the early development of Rayman 2: The Great Escape, it was going to be a 2D side-scroller. However, because of the new and constant usage of 3D graphics in games of that era, the original 2D design was scrapped and Ubisoft decided to make their franchise 3D as well. Details and screenshots of the original prototype can be seen here.
In the German gaming magazine PC Player (issue 01/2000) Rayman 2: The Great Escape was named as "Best Platformer in 1999".
The PSX release of Rayman 2 originally came with a digital watch.
In Japan, purple is the colour of death. Because of that, some characters with purple in them were changed. Rayman's body was made blue, Sssssam the snake turned into a kind of green, and Jano's hat was turned red. But the most bizarre change was made to Ly, who's body was changed from orange/purple to white/pink.
The names of a few characters changed during design of the game.
The original name of Globox was Globber. The original name of Razorbeard was Razorface. The original name of the Teensies was Smalbeings. The original name of Polokus was Polochus. And the robo-pirates were originally named the Mysterious Guild.
The purple general who sells Razorbeard the Grolgoth is also featured in Tonic Trouble's opening cinematic.