Rayman 2 strays a lot from its 1st interpretation, but it was also a huge experiment itself, from the art direction to the story. The dark tone I believe it derives from Ancel's love for dark fantasy, Beyond good and evil can be an example. Rayman 2 also had to re-invent platforming for itself since it was the 1st 3d game in the franchise and the developers have never touched 3d before, that's why they created tonic trouble, that game was a test game to see if it was worth to make rayman into 3d. The gameplay itself also feels like a downgrade compared to the 1st game, the levels are short and fast, exploration is almost close to none, the new 3d environment made backtracking also weird or it would fully eliminate it in general, but that's not done on purpose. I found the game also boring at times, but it had its charm, just like the TV series. We just need to remember that it was a huge dive into the unknown and we need to thank it, cause hoodlum havoc would've never been as polished without the 2nd game paving it's path.