Hmm, overpowered demon summoning maiden of a cult fighting a magnet spaceship thing.
With demons, Amane destroys Magnezone. If it's just her, that's a bit hard to say. A good Fire Dance would utterly defeat Magnezone, but while her magic stat is off the charts, her speed and agility are average at best and her vitality isn't anything special either. At the same time, Magnezone isn't all that fast either, and while it is bulky, Amane hits hard, so I'm going to have to give this one to Amane if she can get off the first hit.
Earthworm Jim Vs. Bulbasaur. Jim may not be the most competent hero ever but with this much of a size and power difference, I think he'd eventually come out on top. Plus, as a worm, he has a type advantage.