Okay, so I decided to do a bit of elaboration on my thought process when fighting Falcon. I get to play Darkrain a lot and I've definitely learned a lot about the matchup.
First off, let's establish that this matchup is 95% about movement and commitment. Falcon can pressure you hard from the majority of spacing positions because he has:
--a speed advantage
--high shield-stun aerials, so you can't shield grab him unless he screws up big time
--a short hop that goes over a lot of your best stuff
--an amazing grab game against ICs! Lots of IC and CF players don't know that his throws have hitboxes and invincibility frames that wreck the ICs anti-grab game.
Meanwhile, ICs must commit heavily to all their actions in advance. Even a simple wavedash has a large commitment to it, because of the distance you travel and the landfallspecial lag.
This means that you have to be VERY cautious about where you maintain your distance and what you do to maintain that distance.
It's also worth mentioning that, because Melee is such a fast paced game, and Falcon is one of its fastest characters, these zones shift CONSTANTLY. Your distance will fluctuate dramatically over the course of a few seconds. Controlling these zones (particularly with ICs, particularly against Falcon) is anything but an exact science. I'm gonna try and elaborate on the tools you have to achieve this, however, and hopefully it will be a bit clearer what the hell I'm talking about.
These images are meant to illustrate some of the ideal places you can position yourself while fighting against Falcon.
This is your target distance from Falcon.
If he attempts to do a slow short-hopped knee, it will miss; same with d-air, obviously. If he does an aerial from a dash at this distance, it will go straight over your head, which means you can easily u-tilt or f-smash him out of it. You are also at a distance where you can react to Raptor Boost, and any dashing shenanigans he does to make the distance better for himself take a relatively long time. If he dashes away, you can dash towards him and then re-establish distance control with a wavedash.
At this distance, shorter wavedashes are your friend. You cannot afford to go in too deep or you risk running into a zone where you are very weak. Likewise, if you retreat too far, you move to a zone where he can dash-dance freely to choose the spacing of his aerials. He'll also be in a position where he can start aiming his dashing aerials without going over your head.
For instance, a position like this. Right now you have no pressure options on Falcon, but he can still pressure you. At a distance like this your best bet is to stand perfectly still. Don't dash, and don't wavedash. If he tries to tip his aerials you can retreat with a dash-dance into a potential grab or dash-attack. If you're committed to a wavedash or a dash already though, then he has a major advantage.
This is another location you generally want to avoid. He has jabs, tilts, short-hopped aerials that he can control the spacing on, and if you commit to anything he has the option of hitting you with Raptor Boost. The only time you want to be at this distance (assuming you're not actually in the process of hitting him or something) is if you're facing backwards; your b-air is a really good answer to many of his shenanigans; full-jumping and b-airing immediately, for instance, lets you hit him out of his short-hopped aerials if you time it right.
In general though, you don't want to be here! Especially since you have to be careful about getting out. His dashing SHFFLs can easily cross you up... or if you wavedash away, you're usually at prime spacing to eat a d-air or knee. This is just a rough location to be in during normal maneuvering.
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Does anybody find this kind of thing helpful or informative? Sometimes when I'm playing I start seeing the match as a kind of battle of negative space and distance, and if I get into the right mental state I feel like I see and control these kinds of zones much better. I wanted to put it into words (and pictures) exactly why, but since matches are so fluid and fast-paced I don't know if this will be of help to anyone.