Go! Go! Kokopolo actually sounds pretty hilarious. That is one PO'd cat.
I've been playing Super Adventure Island II, and weirdly, it feels a lot like a Shantae precursor. It's nonlinear platforming action with plenty of adventuring elements thrown in, and while the design isn't nearly as tight as something like Metroid, it's an interesting mix of the Adventure Island/Wonder Boy gameplay and pretty fun so far.