On the PlayStation1 version of the game, 800 Lums make up The Heart Of The World. All the other versions have 1000 Lums.
Rayman 2 was originally planned to be in 2D, like the previous Rayman game, but the idea was dropped. On the PS1 version, if you complete the game with at least 80%, you can play one of the levels.
When Rayman 2 was ported onto the PlayStation2, it was named Rayman Revolution, or in North America as Rayman 2: Revolution.