Kirby Vs Marth
This is, in my honest opinion, Kirby's absolute worst match up. Marth is just too gay of a character for Kirby to take on one on one. He has the advantage of being both floaty, and pretty heavy, meaning its going to be hard to get him off the stage and even harder to get a solid kill on him. Then there's the ******** range and power on his tipper, but even a non-sweet spotted hit can tear through Kirby. And his grab range, OH DEAR GOD, his broken *** grab range >.<(more on that later) To be honest, if the Marth knows what he's doing in this match, he absolutely wont lose.
First things first, stage pics. Or rather, stages that Marth doesn't have a horribly overpowered advantage on so you can't possibly even hope to harm him. Your choices here are Corneria and Jungle Japes. Thats it. And they are only good for you if your better at camping than he is
Stages to avoid: Yoshi Story, FD, Battlefield, Dreamland 64 and Pokemon Stadium. And those are just the stages that Marth gets an AMAZING advantage on, all the other levels just give him a moderate to above average advantage. FoD is supposed to be a bad stage for Marth, the problem is that in this particular match up, its pretty much worse for Kirby
So yeah, you haven't even begun the match and your already at a horrible disadvantage.
Now on to the important stuff, the actual match. First off, let me just say this, being the aggressor in this match will only hurt you. You have NO good approaches against Marth and as soon as you enter his happy zone, its lights out for you. Unfortunately, the more basic Kirby strategy of crouch->retaliate, is not going to work in this match up. Marths Dtilt/Fsmash outranges anything you can do from a crouch. You also cant trust the ledge because tipper >>>>>> Kirby ledge games. If you want to actually be able to compete in this match your going to have to play a little differently. I've found that this is much more of a waiting game than alot of match ups. Shield camping is your friend, as is light shielding. But you cant be careless with your shield, just sitting there with it up will get you grabbed. Your going to have to keep moving, make it seem like your approaching/retreating then shield the incoming attacks. Your gonna have to take a few hits, and wait the Marth out untill he makes a mistake. From there, its just a matter of punishing his mistakes as well as the situation will alow and then retreating before the Marth gets free and absolutely destroys you.
I find that it helps to have your back against a wall in this match up as it gives you something to transfer some of your momentum to if you take a hard hit. Its also something that helps you actually combo when you manage to hit Marth. Utilt->Bair works a whole lot better when Marth cant escape from the attacks. The big negative here is Marth's short hopped double Fairs. Against a wall gives you no where to escape if he gets you in a Short hopped double fair frenzy, and it will lead to some serious damage. And while on the note of serious damage, remember that most of marths moves become killers when you hit triple digits. You'll have to start avoiding more than just his Fsmash, you'll also have to look out for Utilt/Dtilt, Uair and even Dsmash(although its rarely used)
So yeah, not alot of help I can give you for this match because Kirby is pretty helpless. But wait, theres more. I haven't touched on Marths grab game yet. The big thing to look out for here is the Fthrow. If you DI it towards Marth he can simply regrab you. And as soon as you DI away from him, he can just Fsmash you. Oh yeah, and it will most likely tipper. Isn't that nice? Fthrow->Tipper. Just perfect
So how do you avoid this? Well, the solution is very simple. Just don't get grabbed. How do you do that? Well, you can just crouch under the grab. Whats that? You say I said that crouching isn't good for this match? Well, its not. BUT, if you can see a grab coming, crouching will work, and you can retaliate with a Dsmash. The problem here comes from Marth's broken grab range. If you're in the air, you cant crouch, and his grab range > your aerial range. And if at any point you tech in this match without some crazy momentum to carry you really far from Marth, more likely than not, he's going to be able to grab you out of it.
But what about Kirby's grab game you ask? The thing I spent so much time explaining in my Captain Falcon post? Forget it, doesn't work here. Dthrow tech chase isn't going to work in this match up as Marth's tech goes too far too fast and technically Marth doesn't even need to tech the throw, he can escape the stun before he hits the ground. Your best bets in this match is either Uthrow for damage and a way to escape, or Bthrow and hope you can get a Bair in afterwords. Other than that, not much going on for Kirby's grab game here
A few other things to remember about this match up. Do like Hylian did, Dtilt > Dsmash as an edge guard as it has greater priority. FC is NOT to be used in this match unless absolutely necessary, and even mean when recovering. If you can air dodge to the ledge, thats what you should be doing, because Marth's Dtilt will **** your FC. The ONLY time you should use FC is if you are absolutely sure you'll sweet spot the ledge or you absolutely CAN'T get to the ledge any other way. Also, don't use stone, but I guess that goes without sayin XD.
Edit: Nice sig Rabbit