I'm going to write this as I watch the video and so my comments will be "In real time" (be forewarned, lot's of theorycrafting)
0:40 - I like how you started, really strong and overpowered him. You spam game was precise and on point tot he point where you completely shut him down, that is brilliant. Now he's at 91%, he's already within kill % in that if you throw him off stage he won't be coming back
if you gimp him. This is the first problem I've noticed. You're not following him off stage nor to the ledge. Mac is horrible in the air and when off stage at the angle he was after your Bthrow and your upB the only thing he can do is use his double to try to make it to the ledge. In both occasions you could have gimped him easily if you had either followed him offstage or just used your projectiles more efficiently. For example, after the Bthrow instead of doing a SH backwards into Gale you could've thrown the gale from there or even jumped off stage and galed him. You would've killed his momentum and he would've been either dead or forced to do a side B. In this case, expect a side B and use an arrow (since the gale might be on cooldown) or even zair to stop him. He is dead already considering that he has no second jump, no momentum, you're off stage ready to follow up, and all his recovery options are gone. Remember that Link can make it back tot he ledge from almost extreme conditions now, Little mac can't make it back is he counters at ledge level. That is the other recommendation I was going to give. Simply stand ont he ledge and bait a counter. Many Little Macs use the counter as a recovery option, if you bait it they won't be able to recover since Mac can't do UpB fast enough to regrab the ledge from an empty counter.
In synthesis, don't stay int he middle of the stage waiting for him to recover, chase him and gimp him.
0:47 - He just landed a KO punch on you. The problem I saw in these 7 seconds is that you became either complacent or scared. You lost that momentum that gave you the upper hand at the beginning of the match, and it started with what I said before, when you stopped your offense to spam from the stage and allowed him to recover. At 0:40 you chose a dmash rather than a fsmash, I'd say that's a wrong call. A fsmash in this case would've given you his stock since you were at tip distance and he was within kill % for tipped fsmash. Also, after your dmash launched him in the air again you didn't chase him. You stayed put and threw out a bomb straightly ahead of you, not even directed at him, and after he jumped over it you were too slow in that usmash because (i'm guessing here) you were expecting him to be hit by that bomb, so him jumping caught you by surprised. My advise, again, is to chase him or at least throw the bomb at him to either force a jump you expect or an air dodge you can punish. The important thing to remember is to always have a back up plan in case your action failed, try to always know what will he do next (i.e. reading him). Remember that Link's projectiles aren't only to rack up damage, but also to force situations.
Finally, right before the KO punch, you didn't cover your landing. It was obvious that he was going to go for it due to the landing lag. You tried to usmash upon landing and that's too late (as you experienced first hand). Better options would've been to either go for the ledge via a tether recovery (that way you avoid getting hit from the ledge), use a projectile to cover your landing or even land with a FF nair. You would've either hit him or forced him to shield and thus given you a couple more secs to dodge the incoming KO punch. At 91% dmg a fresh nair would've reset the fight entire since it would've sent him to the other ledge.
1:07 - Your game changed entirely now. You're not as aggressive and are trying to play more conservatively. This is understandable but it's also hurting your game. You are spamming while still, and that makes your projectiles predictable. Predictable translates into easily avoidable which leads to punishes. Keep moving, jumping backwards, keep him guessing. Also, again, remember to chase him more. Yes he can counter you, but you knowing that he can means you can bait for the counter and then punish. Link has a really strong air game with dair and uair that Mac just can't compete against.
1:24 - You're retreating towards the center of the stage. That's Mac's territory, he owns it. You should be retreating and staying near the ledges sot hat you can capitalize on any opening to send him off stage.
1:28 - That usmash was completely unnecessary. Something I've noticed about most Link mains now a days is that you guys don't grab anymore. You are afraid of missing and the resulting punish so your reaction is to almost never grab. An appropiate reaction would be to grab smarter. This is a prime example. Due to where he landed Mac only had 3 options: Get up where he was, roll backwards into the ledge, or roll forwards, which he did. He started rolling as you were still running, so you knew where he was going to be. You should've gone for a grab. Link's tether grab means that if spaced correctly, this scenario should always result in a grab, always, and then he'd be off stage again. Try to grab more, don't be afraid of missing. Friendlies are there for lulz, experimentation and to learn. Don't try to win everytime, try to learn and improve. Miss, fail, get punished, note what happened and adjust accordingly. Basically, start incorporating more grabs into your game. Right here in your match, that should've been a grab and Mac's first stock.
1:38 - This is what I was talking about. You followed him and, while it wasn't necessary, give him extra pressure which will help you. Also, you went for an nair, and that's great, but try mixing bair as well to create stage spikes now and then.
1:41 - You went and waited for him int he center of the stage and held your shield. This is like asking to be punished by Mac. Keep to the ledges and spam him forcing him to approach in a predictable way.
1:50 - This is a criticism in general, not just for this MU. Don't do this of staying put and taking out a bomb when your openent is in the air. If you won't chase him, then retreat as you take out the bomb. Don't be a sitting duck since other chars withe better air game will punish you hard. Retreat and spam or tech chase, don't just stand there and take out a bomb which you then wasted. If you wanted that bomb you could've taken it out, dashed forward briefly and do a reverse JCthrow. That would've given you an opening for an utilt, another usmash or a tipped dash attack/fsmash that would've sent him off stage.
2:00 - You're making his life easier by falling towards him. If you will, then cover your landing, or else force him to follow you towards the ledge. you know that Mac won't go into air game, most he can do is wait for you to land or try to land an UpB on you (which would've killed you). Most Mac players will just wait for you to land, act accordingly.
2:04 - You took too long to go off stage, and when you did you did with a full hop which game Mac enough time to recover. You should've thrown out a rang from a SH immediately or done a SH and gimp him low. Link can recover this time around, certainly more than Mac, so don't be afraid of the off stage (which I get a feeling you are).
2:14 - That's exactly what I was talking about.
Here is my match with SmashBoard player Viewtifulduck82. His Mac always give me a hard time and he keeps me on my game, I am finally nailing wins on him but its not consistent. Check it out and please critique my Link!
The fact that you are starting to take games is important, it means you're improving. Don't give up and don't let loses deflate you. See every loss as a learning experience and grow from it. This was a good match but there are some critical problems in your game play, specifically your gimping game. I may be wrong, but it still seems that you are afraid of the off stage. Don't be, if you are it's because you don't feel confident/comfortable/safe. chances are you haven't experimented with it. Go to training and push your recovery. See how far you can go both horizontally and vertically (down) and make it back. See what what you do off stage from which angle and make it back. Do this in every stage until you
know your recovery options inside and out. lose that fear of the off stage, specially now that we can actually recover.
Well, I hope this helps and makes sense. I never critique videos because it takes forever to do it right and I hate doing it wrong. Why do it if I'll do it half assedly right? Anyways, what I'm trying to say is that you caught me int he right mood and don't expect this to be the norm.
Your Link is good btw, but it can be better. Get to work on being a more dynamic spammer and on your ledge game.