First off: Round 2 at 3:33, Brilliantly executed Uair I was quite impressed.
On your gameplay though, I gotta say you have a pretty adept use of the grenade. I was impressed at how well you used it to limit his movements and at times punish his actions, but you tend to rely on the gambit of the opponent not paying attention when using it. Try cooking the grenades for a bit or pull one out when he charges and shield so the grenade explodes on the attack but you remain safe. I was disappointed at your lack of Nikita though, it's a great KO and Edgeguard tool if you practice with it right, and you wont have to risk ROB burning your face off when you chase him in the air.
Your C4 use, I was a bit perplexed by it. I noticed that you tend to burn through them quite quickly, as if you are using them defensively but hoping to KO with them. If you are doing what I think you are doing and trying to score KO's from it, try getting in close to stick it on the character instead of leaving it in plain sight for them to dodge. Wait for them to charge and powershield-stick it on them or try a Dthrow in order to techchase them for a stick. If you are trying to use them defensively, dont burn through them so quickly or else your opponent will read your actions. Just leave it there and pressure your opponent so they wont move far and you can use it if you get the chance to throw em there.
Your use of the Usmash to cover some of your bases was pretty nice, but I also noticed you tried to use it as a KO move as well. People can DI out of the way if you try to directly use it as a KO, so just stick with defensive purposes that way you can attain a KO if they try to gamble. If you want a KO that isnt just Ftilt, try Utilt or the more impressive Uair since they have outstanding knockback and you dont have to worry about them DI-ing out of the way. On the topic of Usmash, why arent you Mortar Sliding ( XD )? It's a really great defensive maneuver that also grants you great mobility as well. The dash attack also pops the opponent into the Mortar line of fire also so it's a great way to score KO's as well.
It's a fairly decent Snake, you just tend to be more blunt and less tricky. Constantly spamming grenades and burning though C4 was your demise since it gave your opponents a key thing to look out for. Try to mix it up that way he won't read you as easily.