In the first match, you are way too predictable with your recovery. You just got out played all over in that match, and you got a lucky first kill or else you wouldn't have even been in that game. Also, you should learn to QAC. I don't think I saw a single quick attack in that entire match, and you need that mobility against marth. All around, you weren't campy enough. You need to use your projectiles more and camp the eff out of that ledge if you want to beat a good marth.
Did you notice how he was outspacing you the whole time? Part of that is the matchup, since marth's sword is longer than your entire move list. But part of that also is that you were letting him get in his range. Against marth, you really need to either be outside of his sword range (which is quite far considering he can step in with dolphin slash) or all the way inside your tilt range. You spent a lot of time right in the middle range, where Marth is god.
When floating down to the stage, you tried to time air dodges but got predicted (because you were predictable) and hence got ***** there a lot. You need to use your B moves to vary that whole situation up. Don't just tumble towards the stage. Use neutral b to give him a reason to stay off your path for a moment, and use quick attack angled away from him, and down, or straight over, and then down.
Your off the stage game was not good. Seriously, go play a level 9 computer on battlefield, and do whatever you can to avoid fighting for 8 minutes straight. Play ledge games, look for the cpu to make mistakes and get in a free ledge-hopped fair. Then ledge camp again and wait for another mistake. Learn how much you can screw with quick attack off the stage. You can even drop and immediately do an overB right into the ledge and grab it again. Also, you can drop, charge over B, shoot under the stage, second jump, and then quick attack at two angles and grab the opposite ledge. Pikachu's ledge game is really good if you'll learn it and use it.
I hope this stuff helps.
edit: ryoko is good at DI. You aren't so much. I'm not going to explain it, cause I'll probably explain it wrong, and it's honestly one of my weakest points too, but learn how DI works, and watch the best pikachus when they get smashed.
Also, we should see more autocancelling with your nairs and fairs. You tended to full hop with your nair coming out at autocancelled timing. if you would just get good at shorthopping, you'd be shocked at how much faster things would feel.
another trick that you didn't use was Down smashing people as they are coming up to the ledge from below. If they aren't perfect, you can actually spike people out of the bottom of the downsmash. It's rather satisfying to get kills that way. You'll often have to edgehog after the spike to get the kill, but that just makes it even more fun.
Another thought: When your opponent is at low %s, it's ok to Forward smash a lot. When they are at really high %s, it's ok to use it again. But when they are between 40-80%, you should pretend you don't have a forward smash. You are keeping it really stale, and it's one of your best kill moves.
The primary difference between the first two matches is the spacing. Pikachu outranges TL on the ground. Ryoko spammed backairs like he was getting paid to, but it just doesn't have quite the spacing advantage that marth's entire moveset has, so his timing mistakes and predictability was more punishable because you have a greater window of getting inside with prediction and good timing. I'm guessing you get ***** by good snakes, G&W gives you trouble, Olimar gives you fits, but that you do decent against Metaknight, DDD, Falco, Wario, and maybe lucario. Just speculation there, based on the spacing issues i see.
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