I was actually being completely sarcastic.
If MercurySteam is going to tackle Contra, I'd like for them to at least attempt to translate the frenetic, bullet-hell combat that made the original so exciting. If I'm not dodging bullets, then it's not Contra. That about defines the series, along with maybe aliens. I care more about the bullet-hellness than I do the aliens, though.
If they can do it in 3D, fine, the more power to them, but considering the precision those games require, I have to imagine that a 3D version wouldn't be as good as a 2D version.