S Tier
Lucas
The process stock-elimination is less guaranteed, though with a much less demanding base.
Meaning, there's no hard read tech-chase-style needed with the ease of combos on him, and it's not a free-FULL-recovery if he DOES get through and on the Stage somewhere spacie-style, but there's a much more dynamic process for option-elimination towards killing him with the same turn-around in advantage that spacies have when doing so.
Wario
Free kills every 90 seconds on top of a character that is BEST POSITIONED WHEN ATTACKING due to the actual safety and dynamics of defensive offense. Like really, any character that literally is at their best in regards to both safety and killing opponents when flying straight at the enemy, and has a free kill move, is like Jiggs on hard drugs and drunk. Might as well be Wigglytuff, or Chansey with infinite speed and critical-hits. Though his feet shrunk a little, and he can't actually fly.
Wolf
Stale-mate master, in the sense that if a mistake is made, it's a stock loss below 70% from both sides, so nobody will want to try making anything happen from nothing... good thing Wolf can MAKE things happen from nothing better than almost anyone. The more patience comes in these matches, which will be essential, the more he'll shine. It goes both ways, so he has his same advantage against him too.
A Tier (more polarizing and/or gimmicky)
Metaknight < trade hits with this guy, it's the best bet to not be out-... everything'd
Zero Suit Samus < never committing to maintain control from positioning
This is as decieving as it gets. DD into Pivot D-Smash and Up-B OOS with Grabs to follow them, Hail-Mary Dive-Kicks off-stage for edge-guards and combo-ending on a whim, and you'll accomplish more than most characters ever will, while feeling like you're not even getting much done. Oddly never afraid of ZSS, but oddly somehow she does amazingly well, a lot < common thing that will spread like a cuties.
Mario < staying where he's trying to lock you out of to make him commit
Locks-down everything, and goodies to boot. Issue? Stay where he hates you. Seriously, the one down-fall of this character is that he CANNOT keep people out of where he doesn't want them for ever. He can make it hard, and risky, and annoying, but it's still on stubby-arms to commit if you ever get there, even if he's controlling the pace and positioning of a match 99% of the way through. He's so good at it that he's almost S, but he's still got a sweet-spot against him.
Fox < taking risks for small rewards to start a stock elimination process
Everyone knows Fox. How to beat Fox? Small risks for small rewards. You have to take them, and most characters will struggle with these trades and risks due to lack of process-game to make as much of them as Fox does. It's still there though. Sheik can still Needle for some %, get a knock-down on a Hail-Mary Dash-Attack, and end it. Project: M has enough dynamics on every character to make this simply too breaking for Fox to be unprocessed enough to be the best.
Luigi < gaining small rewards for control while avoiding possible risks
Run for your life and camp. Delay the game and pick him off for chasing you if he leaves the opening with over-extensions. Big stages both hurt and help him, in that he can kill anyone off any hit easier than anyone else, but navigating well-spread platforms can be hazardous in a chasing-game. Non-committing games will be boring with a few exciting things during kills, otherwise, expect instant-kills and tension filled fast-paced camp-fests.
Peach < out-mobilizing and avoiding possible risks to make her commit
Big stages allow good room for dealing with her, but she still has the POW and the never-forget-any-stock life-spans of years. Aggressively passive play master, thriving off aggression while never really committing, perfect beast of the niche, and perfectly fitting being so good at a specific style. Will win lots, but will have her serious adaptations to do along the way.
B+ Tier (death-touches and fortresses) Basically still Top-Tier style
Snake < mini-Peach with less diversity but more ToD's and polarity both ways
Same as Peach, but lacks the POW while having the BANG. Has less light-reads that lead to stock-elimination, but has more stream-lined variations of offense to make up for it. Niche, and more direct with less diversity. Perfect spot again, though more polarizing in all circumstances.
Pit < mini-Mario with more stale-mate/lock-down flexibility, but less good polarity
There's less of a stream-lined sour-spot in terms of where he's trying to lock you out of, meaning there's more room to play for both parties, but less insurance from both as well. More flexibility in sour-spot abuse allows more of the cast to abuse this, but not excessively due to the complexity of it. He can lock-down in a way that forces committing from the opponent, so it's all in the play that makes a difference. Why he's so good, is that it applies to all, and so he won't be cheesed or forced in any way himself universally. Well balanced.
Falco < mini-Lucas with more polarity both ways, but less flexibility in lock-down/process
He has too many holes to cover to not be abused. There are so many dynamics in a well-spread cast full of well-spread options and styles each, for him to be able to lock them down and pick up on what he needs to in a single swoop. Choking people out with spacing and pokes until they break with a means of trying to pick him out of one of his holes while he doesn't let himself fall to the trap, is a lot harder than finding the holes in Falco's coverage of them, but man... he can sure choke people out...
Captain Falcon < mini-Metaknight with less lock-down, but more polarity both ways
Big stages, easy lead-ins with certainty of finishes on more of the cast than ever before, while not really being phased by the over-abundance of diversity since he'll still Falcon his Falcon and DD into Falcon like Falcon, regardless of Falcon, Falcon Falcon's, and Falcons Falcon Falcon... Falcon.
Charizard < mini-Zero Suit Samus with less diversity and more polarity both ways
Just don't get hit, that's his only issue. Pivot Jab/T-Tilts/Grabs, play a safe game while remaining a threat. Go for Hail-Mary's, rather than camp. Attack on whims while not getting caught out in pressure. Trade those Up-B OOS and fading F-Air into Jab/T-Tilt walls with incoming aerials more than moving around for Grabs or approaches even. Just hit the enemy and laugh at how easily stuff happens, while avoiding getting hit, because you in hit-stun should be the only time the enemy will ever feel safe from death-touches.
B Tier - Would STILL be in the Melee Top-Tier... Just with some splitting in diversity of match-up spreads for them
Donkey Kong
Just hit him in the face and spike him and you'll be fine. Otherwise, don't get Grabbed or your death is free. It's like Falcon, but you need to commit to more offensively to get certainty in the form of keeping him on the defensive. There's no safety at a distance, so the chore isn't lock-down in the form of non-committing outside of pressuring him, but rather in the form of maintaining pressure and avoiding the need to ever being in a non-committing position, because that's what he likes too.
Pikachu
Stale-mate in scary-zones, and just be in scary-places. Things will work out. Really well too. Pikachu doesn't have to do anything to force the enemy to do something, but neither does the opponent to make Pikachu do something, so what happens? Intense suspense, first one to crack under the pressure, loses. Pikachu never has to crack with his speed and safety in a non-committal position, so like Pit, it comes down to play, and being able to have this apply universally is what makes the dynamics give Pikachu an edge in Tier.
Toon Link
The reverse hit-box on F-Smash is my fave reverse hit-box in the game. That is all.
Ivysaur
Like Goku said to Cell, "Back Gohan up into a corner until he has nowhere to go but right through you" so just go right through her and you'll be fine. She's scary, but being on an actual 'defensive' is where she falls apart. Make that happen, and all will be well. All Ivysaur's game will turn to covering holes more than pressuring with holes, akin to Falco-pressure nature, because of her actual sour-spot on her(its/his) face, just like Falco with different dynamics.
Sheik
The dynamics for everything, tool overlap and soon. Everyone knows Sheik. She's good, she's hawt and fine. Stale-mate champ returns, just a little more spunky flare is required in place of the little less dominatrix glory.
Link
Solid backbone for the niche he fits into. No glaring flaw, while his actual overall game-plan is his glaring strength. We know what Link does, and will try to do, but how will he do it? That's where Link will get his wins. He can do a lot, and the dynamics of this are too complex to directly pin-point a scary-zone that hurts him, from pressure to offense to space on the stage to bother controlling, since he won't really break under any particular thing, but may find some way to break you if you're not careful.
Marth
Big stages hurt a bit, sure, as everyone knows. He's still Marth though. Always scary, always tiara-styling, always DD Grabbing, Free-Kill Spiking, and TIPPER F-SMASH FROM NOWHERE(ING) against a cast of people that like to not be able to punish F-Smash as easily as spacies/Sheik, or have more linear play (less DD's that > his own) for things like Counter to come into play more. He's fine, perfectly fine. Always Marthing.
Bowser
There's always something someone can do against him. Up-B doesn't work against feet spaced in your face? N-Air/F-Air back, or WL into F-Tilt/U-Tilt, or something. Can't handle Pressure? Up-B, Side-B to counter something, Down-B WL to safety/counter, D-Smash on a whim even. Jab? Firebreath? For a character that can be countered with so many linear stream-lined concepts, he has everything needed to counter all of it, so it becomes a very cheesy game. Do turtles eat cheese? Bowser must have mutated from it. Don't get Up-B'd, space crap on his face, and be patience. The smell of cheese will go away.
B- Tier = The High Tier of PM, like... bottom of Melee Top Tier... or soething... like Falcon-Tier or something... like ICs-land...
Ike
Pressure him, don't let him move around freely. He's too good when he's moving. Luckily he can be stopped from moving, by hitting him first. N-Air and Garb Too stronk.
Lucario
Trade, and don't crack under abundant resets when not in full raw-neutral control. In think this is like a Jiggs vs Marth match-up with every character in the game. Marth will control 90% of a match, and can still lose hardcore. Lucario can be controlled, but can easily maintain control if he ever gets a hit. The loop is stronk in this one.
Ness
Make the little boy commit. Force him to attempt a Grab, or try an aerial, or back away with a PKF. Just get him to do something and don't get caught by it. If you're slow and immobile, good luck, if you have any general speed and diversity with it, then just run around him. Otherwise he will kill you, because he totally can. Even a bit of % and a bad position, and he'll run you over if you get hit, so the first one counts the most. His punish and few key tools in neutral are stronk.
Diddy Kong
Offense. Don't let him DD, don't let him set anything up. Passively aggressive (DD back at him to make him scared) or aggressively passive (empty SH near him and approach with shield to scare him). Attack him if he does anything, you'll win the trades. Otherwise, be prepared to be slowly chipped out of % and position until you actually die to what before was barely meh. His control is stronk once it's going, like loops.
Jigglypuff
Still a monster in cute-form. Everyone knows Jiggs. Big Stages, diversity in cast, including characters that hit harder with more speed and range. Makes it tough, a lot tougher, but it's totally manageable. She totally still has Rest and B-Air and speed and mobility to make them work like beasts.
Sonic
Speed makes him work in any setting or match-up, so he's good to go with Dash-Stuff alone. This gives him the loops and control like others, but with a lack of diversity in them, making it polarizing. Just as functional in raw-neutral, and just as functional as a character, but it's stream-lined enough that there will be something that crushes it, and while it may crush some things more than others, in a well-spread game, lack of universal play in a niche of process and reset control leads to breaking things and being broken, even slightly. Don't be broken by Sonic, and things should be fine. Sonic can break things deceivingly well though.
Zelda
Don't get touched, and things should be fine. Like... screw attacking her altogether. Almost got a combo going? Watch for N-Air/Death-Kick/the B button. Trying to bait something out? Watch for nothing as she lands and DD Grabs out of nowhere. Just... That shouldn't be a problem, since she's so slow... right? RIGHT?!?! You don't have to go to her if you don't want to... RIGHT?!?! You don't have to hit her, and you can still win, RIGHT?!?! RIGHT!?!?
ROB
Captain do-one-thing-and-win. Seriously, Aerial/Tilt > Laser. Gyro > Grab > Laser. Anything > Laser. Set yourself in a weird position and attack the opponent > Laser. If ROB has ANY pattern, EVER, in Neutral, find it and punish it. He's linear, from movements in neutral to finishing combos, so challenge him in the air if you think he'll Side-B, you'll probably hit him before the move comes out. Challenge him if he's far away, since he's even more linear if you catch him before he changes position/gets in the air. Just challenge him, and don't get hit for simply being too slow to challenge him. You'll see him coming so far away that you shouldn't get hit anyway... really. He still hits hard though...
Mr. Game & Watch
Up-B > FF B-Air > Up-B > FF Bacon > Up-B > U-Air > Bacon > Jump N-Air
^ Stuff like that.
Funnest vortex game ever, that is all.
C Tier
King Dedede
Still a monster, and deceiving, and scary, but like... he's all just a scary monster. Not a REAL Monster, really.
Squirtle
Aqua-Jet all day-can't touch this naa na nana-can't touch this
Side-B getaway-can't touch this naa na nana-can't touch this
WD Bubble face-can't touch this naa na nana-can't touch this
Ganondorf
He's still good old Ganon, just ACTUALLY good now. He still has the good old Ganon syndrome though.
It's different with Ganon than almost any other character (Zelda/G&W/a couple others fall into this category too), it's just a little LESS of an issue than ever before.
In Smash, Ganon doesn't hit you, you get hit by Ganon.
Now... at least we can say A LITTLE BIT, "in Soviet Russia In Project: M, Ganon hits you.