Know any platform/rpgs similar to Wonderboy 3/4/5?

I'm hankering for some old fashioned 2d platform/rpg goodness in the style of the later Wonderboy games; 2d, side-scrolling, with plenty of platforms and beasties, shops and NPCs, etc.

Anyone have any suggestions?

Have you played Cave Story or looked into The Underside (not finished yet), or maybe Akuji the Demon? These are all free, retro and cool. Maybe not 100% like you want but decent anyway. You can read about them all on www.binaryjoy.co.uk , use the search option.