Pika < Luigi
Pika =/> DK
Pika =/> YL
Pika = Link
Pika > Zelda
Pika > G&W
Pika =/> M2
Pika > Roy
Pika > Yoshi
Pika > Ness
Pika >/>> Kirby
Pika >> Bowser
Pika >> Pichu
Pika < Luigi:
This matchup is really rough for pika. Luigi's aerial priority and floatiness is huge. Comboing him is very rare (outside of like uair>uair) as his nair will stop about everything. He'll win a lot of air->air confrontations as well, with any aerial. He can combo pika with nair->anything, but not much else. His ground game is decent as well, with wd->tilts and dsmash. Pika's main advantage in this matchup is gimping ability, as luigi's recovery is just awful when he's hit over + down. If pika can set up one uair spike offstage, it usually results in death, as pika has more than enough edgeguaring tools to prevent luigi from getting back. Just everything else in the matchup is against pika pretty much.
Pika =/> DK:
I'm kinda on the fence with this. I've had a decent amount of experience playing Kwan (notable NY DK), as well as rockcrock a couple times, phish-it, and a couple others. It feels like Pika has all the tools to rush down DK and keep him constantly pressured and with few options. Jolts either force him into shield or into the air. If he shields, you can poke his shield with dtilts/ftilts, or threaten grab->uthrow->dair/nair->combo or dthrow->techchase->option. If he jumps, run under him and now you have an advantageous position as his best options are like dair (not so hot), fade away bair (usually impossible to hit with as long as you keep up with him), fair (slow and easily dash dance punished), or just trying to get back to the ground/ledge via double jumps, air dodges, etc. Pika, however, can start combos with aerials (uair, nair, fair) or usmash from this position. Pika combos DK pretty well, uair spikes can hurt his fairly horizontal recovery, and edgeguarding DK isn't too bad. If he goes high, uair spike. If he upBs to the ledge and tries to tech, jab is untechable and will hit. If he spaces it to sweetspot, step forward to the ledge and down-angled ftilt (you have plenty of time to do so) will hit, or just wavedash onto the ledge->roll. Or ledgehog->drop->dj nair until he dies. Or pika can sometimes chase DK off the stage and just aerial him to death. Plenty of options. What DK has, however, is a brutal punish game. Bair can be hard to get around if you don't have the space to throw jolts at him. And if he grabs pika, it hurts a lot. Low percent grab will lead to at least 3 uairs if the DK knows the timing. Higher percents will lead to death by uair. I'm leaning Pika > DK, but Pika = DK is also fine with me.
Pika =/> YL:
Projectiles can mess with Pika's mobility, but often just keeping pressure on YL can alleviate this. Pika has the mobility to get in on YL, and once you do he won't be able to projectile you, and he doesn't have much to do against you out of shield other than sh nair. With decent spacing and baiting nairs, Pika can usually combo YL alright and just chip away at him until he's high enough that a solid nair/dair/bair/fsmash will send him off, and edgeguarding YL is pretty easy (assuming he can even recover). Usmash is also decent in this match as getting close enough to YL for it isn't too bad, and it can kill pretty early. YL's big guns are his projectile game, nair, and dsmash. You shouldn't, as pika, be really getting hit by much else that matters, maybe some utilts and bairs. Nair can be hard to get around, but it's easier than some chars'. Dsmash has enough range and ko potential that it's worth noting. And YL's projectile game can limit your movement options, which hurts pika, and if you do get hit then he can follow up with aerials. It feels relatively even, but it feels like pika can usually kill YL earlier than vice versa, as YL doesn't have any really solid edgeguards/punishes against pika, and his kill moves are subpar while pika has plenty. Again, leaning > but I can see = as well.
Pika = Link:
After playing primarily Skler and HDL, this match feels pretty even. Nair is really hard to get around, and his projectile game, while slightly worse than YL's, limits Pika's movements. Link's tilts also hurt your approaches, and Pika has a rough time with this. Link has a few more kill moves than his younger self, as nair will kill earlier (iirc) and upB is decent (mostly from dthrow or oos). Link acts as a slow projectile-throwing wall in this matchup, which can be hard for Pika to get in on. If Pika does get in, then he can do some damage though. Uair sets up aerial combos. Pika has a decent shield pressure game on Link. Edgeguarding Link is usually not too bad, as jolts help a lot with hitting him out of hookshot, or you can just jump off and try to intercept his recovery with an aerial. He will live fairly long otherwise, however, being fairly heavy and falling relatively fast, so getting him high enough to put him offstage can be a chore. Pika really needs to use his mobility in this matchup and get in on any opportunity on Link. I'd say it's pretty even.
Pika > Zelda:
As with most Zelda matches, this is pretty straight forward. Avoid kicks. Against most chars, being at kick range is what pika likes since most can't immediately do anything to you at that range, and you can poke with tilts and do dashdance games and such, but in this matchup that's obviously not going to work. Pika needs to play a hit and run game jumping in with well spaced aerials (too high for kick to intercept well and ending up either too close or far for kick oos to connect) trying to get gradual damage on Zelda, then wait for a usmash opportunity, because that kills at stupid low percents and isn't tooooo hard to pull off. Outside of kicks it doesn't feel like zelda has much in the matchup, dsmash isn't really a threat, fsmash is avoidable, pika shouldn't really be in a position much for anything else to connect as you want to be in and out quickly. Kicks really hurt though : (
Most of the rest of these I don't have much exp at all in though, so take it for what it's worth.
Pika > G&W:
G&W has fair and dtilt, and occasional nair, and that's most of his game vs Pika. Fair can be kinda hard to get around, and dtilt will stab pika's crappy shield more than I'd like, but G&W's game is pretty straight forward and counterable. Both chars will be doing mostly 1-2 hit combos on eachother and racking up damage, but getting in on G&W isn't too horrible for Pika, and G&W will die faster, so as long as Pika is at least trading with aerials, he should come out on top.
Pika =/> M2:
Axe has probably the most experience in the matchup, whereas I have relatively little, so probably ask him. It feels like in theorycraft Pika should have the edge, but in practice it's usually pretty even. M2 is huge, and thus a huge target. His range can do alright to keep Pika out though, as dtilt, uair, and bair can be hard to deal with, as well as shadowpellets being about as problematic as jolts. They each combo eachother alright, and each die around the same time, and each have amazing recoveries that can be difficult to punish by the other. Pika has more mobility, and M2 has more range.
Pika > Roy:
There's not too much scary about roy in this matchup for pika. He can't combo pika that well, doesn't have many solid kill moves, has an awful recovery, etc. The main things he does have is a decent grab game, decent range (though he can't do much with it), and potential for early kills (even if they're rare). Thanks to pika's meh techrolls, roy can techchase pika from grab decently, leading to a potential techchase cg until mid percents that's kinda tough to get out of. Dtilt can be annoying, but it won't often lead to much of anything. Otherwise roy has just a rough time racking damage on pika, while pika can just whittle away at roy with aerials and tilts. Once pika gets a solid hit to knock roy offstage, he's pretty easy to edgeguard as if you hit him with anything (jolt, aerial) or often just ledgehog, he's dead. He also can have a kinda rough time killing Pika as his kill moves can be kinda slow and hard to land. I probably make it sound like >>, which I don't think it's bad enough to merit as roy can still get early kills with grab->dthrow->techchase->fsmash/dsmash if pika messes up, or just get 'lucky' fsmash/dsmashes at mid percents, but it isn't that reliable. Pika > roy sounds good.
Pika > Yoshi:
Shiri will probably argue with me about this, but Pika beats Yoshi. Yoshi is annoying and awkward, but as long as Pika's patient and punishes the limitations of Yoshi's game, he'll come out on top. Both characters have about equal opportunity to screw up / punish the other, but Pika just punishes harder in this matchup. Yoshi's main weakness in this matchup is the lack of a third jump. If you wait out the third jump and spike him after it, Yoshi dies. If you expect him to nair out of it, shield and usmash out of shield or grab->bthrow and force him to jump again, essentially resetting the situation. If you ever catch him after his second jump, or trade with his aerial out of second jump, he'll usually die. Yoshi combos Pika pretty well, yes, but it will less often lead to death than Pika's punishes on Yoshi.
Pika > Ness:
Ness's fair is a decent wall against pika, and fade away bairs can hurt. Ness' dj game doesn't amount to a whole lot in this matchup other than dj fairs. If he hits with dair, it will usually lead to bair/uair, but this isn't often as usually pika can just react and at least trade nair with it, resulting in no combo for ness. On stage it's pretty even overall, each chipping away at eachother and doing the occasional decent combo. What swings it is just the recovery, as ness's is awful and pika's is solid.
Pika >/>> Kirby:
I feel it should theoretically be >>, but I have more trouble against kirbies than I expect. Not sure how to describe the matchup in short though. Kirby bairs and tilts a lot, pika throws jolts and aerials a lot, and kirby dies faster.
Pika >> Bowser:
Avoid upB oos via spacing and try not to rely on your own shield as much and this match is pretty straight forward. You want to stay grounded a lot until you force bowser into the air, with usmashes, grabs, or just general ground pressure. Once in the air, combo him because he's huge and heavy and slow, just be weary of fair/bair interrupting pika's combo, and you'll be fine. Pika combos bowser too well, whiile bowser is looking for single hits. Bowser lives for a while, but edgeguarding him usually isn't too bad, Pika just has to keep racking up damage and wait for a solid hit to send Bowser off, then hit him like once out of upB and bowser can't recover.
Pika >> Pichu:
Pika outranges Pichu for once, abuse it and Pika wins pretty handily. Pretty much everything pika has in this matchup is just plain better than pichu's.