I heard it was pretty good back in the day, I guess none of my friends owned a copy.
The differences are pretty much only graphical changes. Pretty faithful remake, even though it doesn't add too many things to the experience.
As for the game itself, it's a cute and charming platformer. Lots of action and plenty of jumps and near misses. Plus some secrets to be uncovered and found as well.
I had a really good time with Klonoa even though it's a bit too easy and very short. Anybody who enjoys Mario and Sonic should give this one a try.