INCOMING shameless copy/paste. Since I wrote extensively about this matchup in another thread. It's more matchup tips and notes than a breakdown, but I think its useful.
m crash, I'm a luigi main/diddy secondary.
First of all, an important note is that ALL of luigi's aerials autocancel. Also, all of luigi's aerials pick up bananas. The best way of picking up a banana in a landing state is luigi's nair. You can time it terribly and it picks up the nanner anyway.
As for elh's point that "dash attacking is better than slipping on a banana." I disagree. Dash attack, against a good player that knows the matchup, always gets you hit. Wait, caveat, if they're on or near the stage. In all circumstances where they're on or near the stage, you get hit. Tech rolling a banana back usually does not.
My favorite thing to do , is short hop double fair, or double fair to nair, spamming near diddy kong. Its very hard for diddy to fit a banana in the middle of this without getting it caught. Also, if you catch a peanut on mistake, or by necessity, get rid of it as soon as you can, luigi's glide toss isn't THAT good (good enough to make having a peanut a good thing, I mean). Once you have one or both bananas, try to put them in a place that makes it hard for the diddy to get to them. In other words, put yourself in between the diddy and his nanners. On big stages, in other words his counterpicks, a good way to do this is to leave them on the stage behind you. On small stages, put them in the air with uthrows.
Most diddy's are almost hard wired to get their bananas back, or to get in a position of banana control. All but the best or worst diddys feel very very vulnerable when they are out of control of their bananas and have no way of bringing out new ones. On the other hand, all but the very worst of diddy kongs are able to exploit you for throwing their bananas back to them.
When diddy does not have his bananas, you **** his moveset. ****. Move for move, diddy is luigi jr.. And you have the added benefit of being able to predict the fact that he wants to get back to his bananas. If he goes into the air, hurt him. If he tries to roll, hurt him. If he dash attacks, you can shield grab it (!!!). Note about that, throw him away from the bananas, not a dthrow for combos. If he goes for a dash grab, spot dodge shoryu **** him. If he goes for a flip, bair him. If he spams peanuts, powershield them (having a peanut in your hand pretty much ***** your options). Another note, sh fireball to landing fireball rinse repeat covers most options. Spam that for a reaction. Punish the reaction.
Tldr version
step 1: get the nanners
step 2: neutralize the nanners
step 3: **** diddy for wanting nanners
TLTLDR version
P.S. This **** did NOT work on AZ. This **** almost worked on sai90. This **** ***** the piss out of every other diddy i've played (most of whom are better than sai90, none of whom are better than alphazealot.). AZ is just too much better than me. Sai90 has a ridiculous playstyle and somehow does magical things in the luigi matchup (but I still win). Against a much better diddy (az) I just played regular, autoweeg, and did quite well, but still lost. If you run up against a diddy kong that can predict 3 moves in advance where you're going to land, and have a banana there, you lose, sorry.
All in all, I'd cal it 60 or 65 for luigi.
I just read something that requires a response.
Okay i should have been more specific. If diddy crosses over your shield via forward dribbling, u are in no form or fashion going to punish him for it. If u drop your shield u trip on the banana...if u stay in your shield he does whatever he wants...if u jump he hits u with a aerial. Completely safe and can lead into consistent kills.
JAB! Jab, bro! 2 frame jab that cancels into everything in the world! When the hell is diddy going to be so on top of luigi that he can get that accoplished without getting straight up KILLED? Not to mention that Jab to jab cancels on diddy's shield are basically entirely safe and lead to very easy shield pokes. If you're right there and you're not rolling away, GG.