Marth Vs. Falcon
Within the higher tiers of characters, I would say there are two that could be considered Marth's worst nightmares: Sheik and Captain Falcon. Falcon has an incredible punish game on Marth. If he lands a solid hit or grab you can potentially die from 0%, regardless of what stage you're on. His terrific punish game combined with the fastest ground speed of any character, as well as the longest range Dash Dance, makes him a particularly difficult matchup for Marth.
The basis of your entire strategy against Falcon hinges on the fact that he stands very little chance against your options when grounded. When you are aerial however, your options against Falcon are limited, and his punishes on clean hits are brutal.
Your D-tilt is relatively safe when spaced, and can be used to severely limit his otherwise amazing ground movement and speed. Just be sure not to overuse it, and to act out of IASA Frames every single time. As long as you're properly using D-tilt you can be reasonably confident that he will attempt to approach from the air often, usually with Short Hop aerials. You can even bait these by D-tilting purposely too far away, and then anticipating the approach.
You have many options for beating Falcon's aerials, the most obvious being: Ftilt, Jab, Fsmash, and Short Hop Fair/Nair. I personally find that using your Dash Dance to force missed aerials to be a bit more difficult than when facing other characters. In addition to his raw speed, many Falcon players will overshoot their approaches with deep aerials - particularly Nair. This is because Falcon is fine with whatever outcome deep aerials lead to. If you dash back you will often still be hit, and if not he will still gain space on the stage. If you shield the aerial then Falcon will land behind you, which is easily Marth's weakest grounded position. If the attack connects, there is almost always a good follow-up available to him. Even trading hits is almost always beneficial for Falcon. This is where what is in my mind one of the "secret weapons" of beating Falcon comes into play: grounded Side-b. Dash back Side-b is amazing at countering his deep aerials. It may not always combo into anything directly, but it does stop the aerial and at least briefly forces Falcon to be defending. When Falcon is defending, you are winning. Spaced Sideb can be used to hit every short hop aerial Falcon has, without trading. At certain percents you can even safely combo into the second and third slashes of Sideb.
A more difficult but possibly even better counter to aerial approaches is retreating Pivot Fsmash, Ftilt, or even Jab. Fsmash and Ftilt are obviously more punishing, but Pivot Jab is extremely safe. Theoretically a Pivot Uptilt would lead to some of the best possible punishes, but I've yet to see anyone who's able to perform them consistantly enough to be viable. As a side-note on Pivots, Pivot Fsmash is a useful tool in Neutral if used very sparingly. It's rarely ever expected, and is even safe on shield if you land the tipper spacing.
Risk/Reward and Defensive play
As already stated, Marth wins on the ground, and has all of the tools necessary to counter aerial approaches. This allows for a safe and generally defensive playstyle to be effective. This type of playstyle is beneficial even more so because Falcon cannot play the neutral game safely and defensively. By staying grounded and dominating space you can force Falcon to either approach you, or lose to your superior options. However, in order to approach he must choose between his losing set of ground options, or risky and counterable aerial approaches. I would argue that the most important concept to success in this matchup is that you should force Falcon to take risks instead of taking them yourself.
Falcon is extremely fast and thrives with space to move around in. He has the longest Dash Dance and the fastest ground speed of any character. He's arguably the only character with better movement than Marth. It's painfully easy to find yourself completely overwhelmed by his pressure and speed. In order to win you can't afford to let this happen.
The simplest and most important way to control the pace of the game against him is to control space. This doesn't only apply to ground space, it's equally as important to control the air. Imagine the top half of a sphere positioned in the center of Battlefield for example. Stretch the boundaries of the sphere until the top is touching the top platform, and the sides are extending just barely into the side platforms. Your goal is to gain control this space and keep it. Falcon is extremely susceptible to being gimped with early kills off of simple mistakes near the ledge. Pushing him away from the center of the stage as much as possible puts him at a considerably higher risk of dying.
After landing a grab, throwing Falcon towards the ledge is usually the best option. If close enough to the ledge you can cover all tech options with Dsmash, or if spaced correctly with a Dtilt and reacting to tech-in with a quick turnaround grab. If you land a regrab within range to throw him off the stage you can net early, easy kills. If he DI's incorrectly you can land a tipper Fsmash, and a Dtilt is likely to land regardless of what DI he chooses. When you mixup choosing these options alongside Short Hop and Runoff aerials you essentially force Falcon into making a quick decision that has a decent chance of getting him killed, while putting yourself at little to no risk.
Use of aerials
When attacking Falcon be cautious when using approaching Fairs. Often times fading back or short hopping in place with Fair is just as useful and far safer. The same is true with Nair, and I want to specifically emphasize how useful I find shield-stop Nair in place/retreating is in Neutral. However, approaching rising fair is rewarding if it connects. You can often hit the second fair within your short hop and follow-up in many different ways; Fsmash, Grab, Dtilt, or even another approaching fair. Also, approaching short hop Fair into Uair at mid percents can setup easy kill combos.
By mixing up your Fast Fall timings and aerial drifts Nair can be a versatile tool in neutral. One particularly effective position to use Nair is when your opponent is on a side platform. By Short Hop Nairing them from underneath the platform you can get multiple hits on their shield, or even shield-poke. Also, due to hitting twice Nair will throw off most players Shield Drop timing.
Especially against approaching Nair, Crouch Cancelling is extremely effective against Falcon. Attacks like Nair and Raptor Boost can be safely crouch cancelled and punished until mid percents. Falcon's getup attack and attack from the ledge can both be crouch cancelled until very high percents, and doing so allows for easier tech chasing and edgeguarding. Falcon's primary defenses against Crouch Cancelling are his Knee, and his Stomp. By crouching in neutral to bait one of these options you can land a surprisingly easy Standup Powershield. I consider this option, as well as Standup Powershields in general, to be underutilized and underdeveloped.
Reaction Tech Chasing With Grabs
On flat ground you can fully cover all options off of Forward Throw and Down Throw with regrabs on reaction until roughly 40-50%. Back throw is not recommended due to having more frames after throwing your opponent before you're actionable. A good rule is to use Forward Throw always unless it wont knock Falcon down, and in this case use Down Throw to build the percent needed. A concise summary to learn from and expand on: Down Throw from 0% to ~10%, Forward throw to ~40-50%, then end the tech chase with a punish. If you choose to use Upthrow against Falcon instead, I would recommend you use Kadano's comprehensive followup table as a reference for which guaranteed followups are available at different percents.
Edgeguarding and Off-Stage
Falcon has weak recovery options, and Marth is able to edgeguard him relatively easily. When given the option, it's often preferable to force Falcon off the stage even if you have to sacrifice continuing a combo to do so. Unless he's far enough away that he can only grab the edge, you can usually stay on the stage and use Fsmash, Shield Breaker, and Dtilt to deny him from recovering. If he quickly drops low in an attempt to sweet-spot Upb to the ledge you can kill him with run-off Fair, Upb, or even shield breaker. Getting grabbed by the Upb actually refreshes your double jump, so it often isn't a fatal mistake.
For the most part you can punish Falcon's tech options on platforms the same as you would most other character's - by using a combination of Upair, Uptilt, Fsmash, and Waveland grabs. However, it's overlooked how susceptible Falcon is to Platform Push-Offs. His long roll distance and tendency to look for Shield Drops against Marth's platform pressure make it common for Falcon to end up Shielding at the very edge of platforms.
In most matchups, Marth is dominant on Final Destination. This is absolutely not one of those cases. Getting hit by a good Falcon player on this stage is usually a death sentence. Off of any solid hit or grab he's able to juggle you to your death with very little counterplay available. Marth's punish game is good on Falcon as well, but followups aren't nearly as guaranteed or threatening. The risk/reward ratio of winning neutral is simply too weighted against Marth. This is definitely debatable, and playstyle dependent, but I would highly recommend avoiding this stage against Falcon.
There isn't a real concensus on what stages are good or bad for Marth vs. Falcon, but beyond Final Destination it's my opinion that: Yoshi's Story and Fountain of Dreams are best, Pokemon Stadium and Battlefield are decent picks, and Dreamland is the worst stage in the matchup.
TL;DR and High Points
- Falcon stands very little chance against your options when grounded, and you are much less safe when aerial.
- Sideb is especially useful against Falcon's approaches. Retreating pivot Fsmash/Ftilt/Jab can also serve much of the same purpose.
- Trading hits is almost always beneficial for Falcon.
- A good strategy is to be generally defensive and safe, which forces Falcon to take risks instead of you taking them yourself.
- Falcon is extremely susceptible to being gimped with early kills, especially at or near the ledge.
- Often times fading back or short hopping in place with Fair is just as useful and far safer than drifting forwards.
- When chaingrabbing Falcon you should Down Throw from 0% to ~10%, Forward throw to ~40-50%, then end the tech chase with a hard punish.
- Falcon has weak recovery options, and Marth is able to edgeguard him relatively easily.
- As is true regardless of who you're facing as Marth: Stage control is essential.