Any character whose main game plan is tight combo strings and shield pressure (aka every spacie) gets wrecked by Cypher OoS, y'all. Every time I play a melee spacie main for the first time with Snake, they inevitably say "What the hell, I shined you!?" right after I Cypher OoS. They're conditioned for speed and quickness, which means they use very few frames of shine—therefore, the invincibility on grounded Cypher eats it up and punishes them. This leads to C4 sticks on good DIs and resets neutral on bad DI. The other good aspect for Snake vs. Spacies is how mobile they are (with Wolf being the least susceptible) which aids in your strong trap game. Even if they do wait out the Cypher, it tends to trade, which is good for Snake because he KOs spacies far more easily than they KO him. Resetting to neutral isn't bad so long as you can avoid Falco's lasers (Fox's are no problem) long enough to set up mines (which they have to detonate carefully). Once that happens you can just reset the shield trap and force them to have limited options in response, where you then go for grabs, jab resets, etc. If they camp, you camp right back with grenades. Spacies are pretty even and I can't imagine why people have so much trouble. If you adequately punish the approaches (which Snake can do rather easily), they're forced to play a slower game which will be in Snake's favor. Edgeguarding additionally is no problem since Snake has a solid punish against most of their options:
- C4 on platforms to punish high recoveries
- mine on ground to cover edge rolls.
- GRAB LEDGE to force bad options.
- Ledgehop Tranq/aerial to cover any other options (and if they sweetspot ledge you can shieldgrab the standard getup and reset the edgeguard with back throw/dthrow techchase w/ mine coverage.
- dair/fair spike or bair UpB and shinestalls
The matchup is far less dependent on C4 sticks as well since
fair/bair will KO around 20% earlier than a up throw -> C4. If you play the matchup like a Sheik would it goes a lot better: Edgeguard spacies and KO toward the sides. They're fast fallers! Ban FD and Smashville, those stages suck for Snake anyway and spacies generally have trouble coming down against Snake because of grenades, Cypher hitboxes, Uair, usmash, utilt, and mines limiting so many options. Doing SHFFL Nairs, but jumping with Cypher, when they're above you covers a lot of approaches because you have an upward hitbox to cover above you (I'm pretty sure that's the fastest reliable option) that will also hit them if they didn't approach. I do this vs. Falcos all the time and their dair gets eaten up and I get grab off of it pretty easily.
Meta Knight does seem trickier because he has such a potent grab game against Snake as well as disjoints on his moves which make a lot of the above strategies much more difficult. Avoid using grenades in situations where MK can grab since a good MK combos off of those really easily. Place mines religiously and try to mix them up as best you can so that the MK can't remember where they are. Camp him out and force him to approach and get the C4 early. From there, trade with grenades and Cypher until you can KO, because again: MK dies WAY before Snake does. Be smart with your recoveries and know that trading with a grenade tends to be advantageous since it resets your Cypher, overrides their hit trajectory, and puts your opponent in a bad spot. B-reverse every single on stage recovery because that makes it harder for them to outspace the explosion. Use ftilt to punish techchases because it's faster than Cypher and has far better follow-ups than jab. Outside that, Metaknight has huge trouble sweetspotting the ledge, so use that against him with mine to cover missed sweetspots and C4 to cover any sweetspot options (between roll and stand, it can cover both). Cover the platform with your grabs and aerials and don't be afraid to spike with fair or meteor with dair. It's still in MK's favor, but he has to approach, which makes it far from one-sided.
Sonic shouldn't be too difficult if you apply the same kind of concepts for the spacies matchups: Sonic loves fast, tight combo strings and Cypher shuts them up real quick. You just get the added benefit of a predictable recovery, easier upward kills, and far stronger mine abuse given how much Sonic has to move.
I can't honestly say much for the Diddy matchup since my area only has one strong Diddy main and I've only played him once ever.
The real menace I've been seeing is Squirtle, who has all of the movement strength of Sonic WITH knockback armor and projectiles in bubble and water gun to destroy mines. I feel like his short stature also makes grabs extremely difficult, which is the best option vs. side-b at low percents. Zelda is also very difficult because of how many safe on-shield options she has combined with her floaty weight making it difficult to combo anything. Ness invalidates grenades and mines with PK Fire and also has a low weight. Ivysaur and Marth have the proper spacing ability to make any of Snake's options outside grenades very underwhelming. Really, any character that has strong disjoints and/or flexible projectiles is probably difficult for Snake. So, ordered roughly from hardest down:
1. Link
2. Diddy
3. Squirtle
4. Pit
5. Toon Link
6. Zelda
7. Samus
8. Mewtwo
9. Ness
10. Ivysaur
11. Mario
12. Peach
13. Marth
14. Sheik
15. Ike
16. Metaknight
Lucas, Fox, Falco, and Wolf have limitations on both of those categories and also have a great combo weight for Snake. Lucas also gets chaingrabbed to like 50%.Snake's gameplay is focused on building a wall which cannot be broken. The characters above have the tools necessary to chip away at that wall without sacrificing their spacing. I'd argue that most other characters have an even or close to even matchup against Snake, with a few that are clearly in Snake's favor (Bowser, DK, Puff, Falcon, Ganon, G&W).