Hmm. You're right. I just looked at Castlevania I on YouTube, and they are in fact very similar. Zelda II was great, but I don't think people see it as a "traditional Zelda title", because, well... it's not. It's a shame people don't play it as much as others. The new Adventure Time game for the 3DS ressurects the gameplay introduced in Castlevania/Zelda II, so I'll have to pick it up.