Nostalgia is a powerful force. It's why old people buy classic music; it's why people buy lunchboxes of the Lone Ranger for hundreds of dollars. It has an emotional, memorable attachment to the persons inner psyche. That being said I don't like Castlevania from a point of nostalgia. I liked it because it was like a dark Super Mario Bros. and for some reason that worked for me, but I think Metroid is rather dark enough and doesn't need to be ripped off.
What is so funny about the video game industry is it's a microcosm of a movement. Instead of having say the realist movement and naturalism in literature over half a century video games has undergone a myriad of changes in a fraction of the normal cyclical time span of any other genre, or medium for that matter. I've found very distinct era's in gaming. Think about it. Atari was like cavemen with stick figures. Nintendo, then 16 bit was like early societal man, then early 3D and your right into the medieval, now we have realism. This is not just graphical but mechanical as well and that's why we have all this debate over new and old. Older generations weren't meant to live that long in a traditional movement so you have above average grinding and friction as new ideas become the norm.
Just had to get that out. Fabe 3 rocks! Still pissed at New Vegas. We aren't talking, it sleeps on the couch.