Did you read Esam's thread on missile spamming? Do read it. Also, watch his videos. That missile spamming is glorious.
You dash attack a lot. Too much in fact. You dash attack after land-cancelling a missile. You dash attack after your opponents mis-spaces or outright whiffs a move. You sometimes dash attack when your opponent is just close enough that you (probably) feel pressured to throw out a hitbox for the sake of attacking whenever possible. Try not to dash attack too much. You have more options than just dash attack.
You sometimes recover high and attempt to hit your opponent with a nair. I did not see enough punishes by your opponents since they were too busy either getting hit by an obvious attack, or whatever. People can just shield grab, or that Marth, in particular, could have spaced a f-smash. You are better off going for the ledge or firing a missile as you fall towards the ledge and use your tether to recover.
You like to break out of your opponents combos with nair. Although this is an exploitable thing that Samus has, I would try learning or getting used to doing combo di since this will probably help you when combo-breaker-nair fails.
I don't know what else to say. I either lost patience watching how bad your opponents played, or maybe the fact that your videos showed you beating not-so-great opponents leaves me no other means of deciphering other issues you have or remarking on whatever else needs mention.
