After playing through the N64 version for the first time very recently I feel extremely compelled to write this review.
I've owned and played the PS1 version of Rayman 2 many times throughout my life and I am in sheer awe at how much is missing from this release. Every single level in this game barring maybe 2 of the shorter ones had been completely gutted. The only plus to the PS1 version is that it has full voice-acting but this is easily unnecessary, the original's babbelspeak does a good job at voicing any character it needs to.
Please please please trust me in that by playing this version you are absolutely not getting the full and wonderful Rayman 2 experience.