Are people asking me for input on something?
If it's about approaching Snake...
Snake is screwed in his shield, and Marth can bait/**** most things he can do whilst not being in shield. Grenades are one of his only defences and we can handle Snake using them well anyway (aim for his head).
Approaching Snake is reading his patterns of movements, and once you believe when his next shield will be, that's when you go to town.
Usually empty shs into grabs get him ("over relying on grenades"). If he's out of shield you space yourself at his max ftilt range and you make the decision to fair when you're just about to reach his head height (as in you commit to moving in or not).
The main thing that makes the match up easier against Snake is, once you force him into shield, he's like "where's my options at?"
Doing the ZMT against Snake is something i've been doing since mid 09. I'd do a picture (but I'm lazy), but there are distinctively noticeable "zones" around snake which his moves do not cover, and Marth's move set is very able to fill in those gaps.