Well, this is a pretty critical response from me but this should help
0:05- did a dashing upsmash... while they were still on the platform... Two things, upsmash is a kill move, one of the only ones you would most likely have fresh. Don't dash and use it cause the dash still can be shielded and punished.
0:07- attacked a falling Link in the air with a dash attack. Dash attack isn't a good attack. If that link used his second jump and did a falling dair, that would have been pretty ugly as the start of the match.
0:09- did a rising nair when Link returned to the platform. Up-air would have been a better choice considering it's priority. Since Ice Climber have a horrible time attacking through platforms since they opponent can jump and you have poor air speed and is floaty, waiting for him to get on the main ground would have been better.
0:11- did a rising nair when the Link was no where near you... Almost got hit with a dair, luckily shielded. You didn't punish his landing lag though so that was bad...
0:12-0:16- had nana desynced while doing random rolls and spotdodges and had her take damaged and placed further from you. Let her sync witih you as a priority unless you are going to do something about being desynced and rolling shouldn't be used as a main form of ground transportation.
0:19-0:41- major ice cube spamming... might want to work on approaches... Also, rolls in between???
0:41-0:43- your chain grab wasn't the true chain grab since they had to fall into your grab... It was a suedo one like popo's solo down chain except with Nana taking your job half the time... Work on chain grabs...
0:45- roll to upsmash... It's bad to approach with roll, up-tilt would have been better or side smash.
0:46-fullhopped rising bair when they were higher than your double jump... don't do random approaches
0:49- looked like you were mashing buttons in a panic because link was close to you. I got this idea from you chaining a downsmash to your f-tilts...
0:50- another dashing upsmash?!?!? and you did it early...
1:00- if the first ice blocks didn't make it over to Link, what made you think more would make it? Got hit by a bomb that could have been dodged...
During that whole earth stage transition, it would have been a better idea to camp and the left in that corner, double jump to upair if you saw him come and grab the edge on the rock or the stage if you saw a bomb in his hand...
1:32- another unpunished downair by link... Don't use upsmash as a thing to punish someone with... You missed with that approach so many times....
1:35- another upsmash.... T_T
1:45-2:00- needs work on approaches. Got punished so many times for that...
2:05- shouldn't have suicided... Could have timed belay since Nana was still in sync...
2:11- upsmash....
2:13- another upsmash...
2:17- upsmash into the windmill... You can't get killed vertically while under the windmill...
2:22- rising up air as approach on grounded opponent???
2:24- upsmash...
2:40- blizzard would have worked better as an approach. Also, don't roll as much...
2:51- more ice cube spammage T_T... Boomerang goes over that and he was at a distance where he would take little to no damage from the melted cubes...
2:55-3:04- let him snipe you on the platform while you continued spamming....
3:12- upsmash....
3:15-3:17- more spamming.... and letting him snipe...
3:20- upsmash...
3:24- upsmash...
3:26- upsmash....
3:27- same chain grab issue....
3:33-3:37- chain grabs shouldn't be so easy to di out of like popo's solo chain. Even if you spiked, he still could have gotten out of that...
3:40-3:45- spamming....
3:47- upsmash while he was on platform again...
3:49- upair would have been better choice. Punish with more smashes if you can't do a true chain grab yet.
3:51- ??? what was that?
3:55-4:00- spammage and upsmash at platform... again....
4:05-off stage edge guarding with fair is very bad...
4:06- should have seen that edge attack happen and squall away and back to punish...
4:15- dash attack is a bad approach
Well, couple of things. Bad approaches in match and in between stocks... Uncontrolled Ice Block spammagen, no true chain grabs (if you know you can't do them to a high percent, use that grabbing time with approaches instead), so much upsmashing, etc...
Work on your basics before going to a serious tournament or else you will lose. You are lucky that the Link didn't punish all those upsmash es of yours... This is not to hurt you, it's just that you need more basics!