Unico: Mahou no Shima e

Also created by Osamu Tezuka, this anime has the same emotional impact and resonance, as well as a similar protagonist. 

Both series look cute, right? They both utilize styles that indicate the target audience is kids, right? So both series should be light and fluffy, right? Not quite. Kids are definitely the target audience of this series, but that doesn't mean everything is light and fluffy as the creators of both series don't underestimate kids and are willing to let the series head in a direction which is dark, yet still appropriate for the age range of the target audience. Their also older series.