Be wary of rolling away from Grenades. It's actually a really bad habit and one that I'm guilty of myself. Snake's roll has a fair amount of vulnerability on it, and you rolled right into the Ganon's back air and lost your first stock for it. If anything, wavedash out of shield to pick it up and mix up your opponent's spacing. You can even spotdodge the explosion if you're familiar enough.
Okay so at 0:50 you have Ganondorf off stage. What's the ganon gonna do? he's gonna try to get back. You set a mine, awesome: Ganon's at roughly KO%, and the mine will at worst force him into a bad stage position (above Snake). HOWEVER, you run into stage after placing the mine: not awesome. It's not bad, but it's not as limiting to the Ganon as it could be. You see that he went to ledge immediately after you placed the mine—so why not wavedash to ledge? The advantage he gets from grabbing ledge is the invincibility to go through the mine safely. Take that advantage away by taking ledge. Simple as that! However, you can still salvage that situation by predicting his method of dealing with the mine: he needs to maintain invincibility somehow to get back on stage, so there's a few options:
1. Standard ledge getups, including stand, roll, and ledge attack. He is over 100% so all of these options are going to be extremely slow and easy to react to. Position yourself to react to them!
2. Ledge jump. This is actually a ridiculously good option in PM that not enough people really utilize (because it was so bad in Melee). This could probably be covered with an up smash on reaction, though.
3. Invincible ledgehop options. I'm pretty sure Ganon can actually No-Impact Land with invincibility, so honestly, I wouldn't even use this option against ganon and would instead just opt for a washdash to ledge into invincible rising back air. This pushes ganon off stage and his linear recovery is very easy to edgeguard.
Ganon ending up picking option 1 (specifically the ledge attack) and you did well to dashdance grab this, but I think you just made a tech flub and dash grabbed instead of JC grabbed. Snake's Dash grab is
really slow (frame 12) whereas a JC grab comes out on frame 8-11 depending on how quickly you cancel your jumpsquat. I'll see if this is a continuing problem or just a single tech flub as I keep watching.
You let Ganon back into the center really easily. Having Ganon in the corner is phenomenal due to the massive strength of the down throw techchase that BND mentioned. You can literally trap him in the tech chase until he's at a high enough percent to f-tilt KO or what have you. Jumping less would help you here—Snake's aerials really aren't very fast and his jumpsquat isn't either. You could've dashdance grabbed the dash attack (which was really bad by the Ganon) and started the downthrow techchase easily. Lucky, you get a tranq off and f-air KO him.
It looks like you're missing your down air l-cancels. Down air tends to lead to grabs really easily, probably because multi-hits scare people into shielding: you can see exactly that happen at 1:11. I'd like to see you nair more, honestly. If you replaced some of the questionable cyphers you had with Nairs, I think your combo game would start to shine. DACUS is another good idea for quick burst movement options. U-tilt also is really good and combos off of dash attack (these are all thoughts that come up during the semi-combo string from 1:11 to 1:25).
The Cypher into Cypher Up-Air combo at 1:58 was super cute, but I gotta point out the failed attempt at 1:52 as well. Only go for it if you can hit confirm it. If you don't see Ganon get hit, cancel Cypher with a Nair or something. What ledge option do you use to set that up? looks like a ledgejump but I wanna be sure. It's a really good option in tandem with the grenade pressure!
These short hop FAirs that you're throwing on your last stock are really questionable. I'd stop those. Also be careful of grenade trades when you're behind on percent. There's no real point for that and it just makes it less likely for you to survive a slip-up. Also be wary of full-charging your mines in the same instances—if you do get hit into it, you die. Just like in game 1
Posting this now so Idon't lose this 'cause my laptop reset lol.