Not played Kid Chaos yet but I vote for Super Frog: nice graphics & music and it is really relaxing to play unlike Sonic the Headhog (too fast for me)... and the athmosphere beats Super Mario games.
I liked it 10 years ago and I like now.
Fire+Ice is also pretty nice. CD32 version (atleast) has got really sympathetic music... but I think that the game is too hard for me.
Many Sega Megadrive platform games are also very enjoyable and include "Amiga style" graphics: I love Quackshot and Mickey Mania though bought my first Megadrive/console this summer :-D
