Coolies. i'll just do some dot points.
in the situation in the first match, where you got spiked and were still alive (no c4), flying your cypher into diddy's barrels is usually the best option; he'll die too. it's actually a perfectly legit gimping method. also, snake uair will ALWAYS beat his dair.
too much holding of jab. jabs should always be cancelled. the second hit of jab is terrible, and everyone gets out of it. spaced jab beats most of diddy's cqc options soundly, and will often force a roll (react, ftilt/grab) or set up to grab (if the jab was spaced well).
if diddy is running at you with a single banana, you know he has two options; throw or shield. this means you can play a guessing game; dash attack beats banana throw (catches it) or dash grab (beats shield). predict right (they very rarely shield anyway) and then you can get a punish.
MOAR NADES. we can camp him. approaching is generally a bad idea, unless you're either way better than him, or he's in the air/offstage. camp, force the approach, and react. nades also limit his nana throwing and dash attack capacity pretty considerably, which is pretty damn useful. just make sure you're doing this from a distance; once he's inside your zone, you have to get him out with cqc.
also, while camping, force him in the air with soft throws, then aim your nades at him; if he throws the nana, the nade should blow it up, hurting him. this is a good way to camp in general.
in general, your punish of choice should be pivot grab/grab. diddy is extremely safe in shield, and hitting it should mean you get punished. so grab more. he's hard to tech chase, since his forward roll is long, and his spotdodge is broken, but it can pay off if you predict right. also, if he's staying on the ground, move back a little then ftilt1, regrab. if you ftilt1 without moving back, you'll hit him away, and only benefited 7% from the tech chase. forwards rolls should be punished with a dash attack on reaction, otherwise you need to predict. pivot ftilt can punish back rolls on reaction. get up is probably the hardest for me; lucky my brother
always spotdodges immediately afterwards.
also, diddy's spotdodge/rolls and airdodge to ground are stupid. you have to be really precise with your punishes, else you're gonna get juggled. grabs give you heaps more leighway than tilts, since they cover a much longer time period. jab cancel ftilt is still my favourite way to punish roll behind, however. his airdodge to ground normally goes under jab, and banana never hits him in landing (i dont know why, but he will ps it 100% of the time), so dash attack and pivot grab are the only real options.
edge pressure. you're letting him on too easily. utilt beats all options except nana, and nades force him from the ledge. while he should be recovering most of the time, you should be able to deal some damage and force him off again a few times. mortar can be good when recovering, force him to airdodge with an utilt or grabbing the ledge, and the mortar
may hit him out of his barrels. **** when it happens.
if he's knocking you about offstage, save you're jump until you've got space, or until you see a spike coming. you really shouldn't be getting gimped like this. jump back and cypher straight up is often good, or even just jump airdodge. moving back and fairing can also work brilliantly, although its pretty risky.
when diddy has the momentum, you really need to step up your defence. get to ground asap, normally through the use of wavebounces and airdodge, and the occasional bair (the angle diagonally above diddy is good here, cause you're almost guaranteed to trade). once you're grounded, reverse nade, and intentionally ps nanas, cause the nade will blow up in his face. either that, drop the nade, roll back, then return to your camping game. defence is everything. if the game is going to fast, you're probably using.
when a nana is nearby, dont ftilt. snake's feet move really wide, and you slip from a distance. grabbing and utilting is way better.
also, you must live forever. recovering can be hard, but i normally (after momentum cancelling), lob a nade towards the edge of the stage, cypher, and try to land just after the nade blows up. its pretty solid in most mus. otherwise, use wavebounces to avoid diddy and his bananas. in your matches, the diddys weren't edgeguarding properly, if they throw both nanas up and then try to juggle, it makes life really difficult. catch things with bair and mix up your wavebounces. but even then, if the diddy is doing things right, you will probably have a hard time. at least you should deal some residual damage while recovering with your nades. di everything up, since all his attacks kill sideways, and you may sdi out of fsmash. i have sdi-ed out of it and punished with uair/bair many a time.
against sh fair, crouch is incredible. you stand up into a ps, and can punish with a grab/utilt (not ftilt1, he gets hit away). either that or dash attack on normal shield. most diddy's spam this if you're holding a nana, since they'll catch it. if he lands with fair, wait a second, then punish with ftilt. he goes under your grab/jab, and an immediate ftilt1 will hit him away.
when you hit him up, dont let him come down. dash attack is **** for keeping him off the ground, since he can't hit you on that angle, and it covers the airdodge also. watch for the sideB and double jump, then you know he's pretty defenceless. pivot grab covers his landings also. if he lands after z-dropping, uair him from the side or utilt.
defend non banana approaches with pivot grab, rather than tilts. diddy's running shield is ridiculous, and he doesn't slide back at all. grabbing in general is a better punish anyway.
stages... i dislike halberd (too small, nades dont stop ground approaches) and sv (too freakin small). i like cs, since you can camp well, and his nana game is skewed, and fd isn't so bad, since nades stop ground approaches well, and you've got plenty of space to avoid the nanas. lylat is always a winner; his sideB doesnt cancel and he cant nana approach when the stage is tilted upwards. ps1 is always great for us too.
play defence, be perfect with the timing of your punished, and di like a boss and you can win.
http://www.youtube.com/watch?v=lFNRK25gW9o
wish i had more recent videos, but this is about it.
that's about it for now, i have a lecture lol.