It doesn't result in a unfinished game at all, it just adds to it and so far nothing really too special has happened. Zelda you get to have tingle on your gba... whoopity fuck.
In Metroid, having those extras is just a nice little gesture for the people who bought both games. I have no problem with it and it doesn't add to your percentage or anything.
It makes me laugh that your actually aggravated that if you want to
you can have extras.
I don't see why you wouldn't have bought Metroid Fusion if you like metroid anyway. It's a great game.
Mr. Completionist... (aka: guide user)