Wild, I was just playing the Klonoa: Door to Phantomile demo on the Ridge Racer 4 Bonus Disc the other day (comparing the Ridge Racer 60FPS demo to Ridge Racer DS... maaaan, why didn't NST port THAT?!)
Door to Phantomile has a cartoon style charm that the PS2 game lacks... the cel shading is better in the PS2, and so are the draw distance, etc., but Phantomile just makes you smile the whole time... plus, 2D gameplay using 3D graphics was more techno-wow back then. Still impressed with how the PSX game looks. Damn good platformer too.