The whole match keep one thing in mind: Nana ****. Can you do it? Always be looking for moments of desynchronization to exploit. If you focus on attacking Nana, then it will get easier and easier to desynch them because she will receive more knockback than Popo will because her invisible damage meter will be higher than Popo's. Get Nana off the edge of the stage ASAP. A good Popo will, of course, follow and try to save her. You can try to finish off Nana via Fair spike or just by knocking her out too far, or you can turn your attention on stopping Popo from getting near Nana. If you play it well, you can trap Popo out offstage as well. This means you've just earned yourself a stock, because his Up B will do pretty much nothing to get him back. Solo popo can be engaged fairly easily. He's nothing special without his lady friend. His smashes still hurt (maybe even more surprisingly), though so be wary. Finishing him off shouldn't be hard, since his recovery is now the worst in the entire game.
A lot of Ice Climbers will simply spam their freaking Ice Blocks until approach.
1. If you can outcamp them here, then they will be forced to approach.
(If they try to approach) And you know what they're going to try to do? What's that? Grab? OF COURSE! They may also try some dumb aerial approach, but Mario's sexy bair should be able to beat that. Another option they have is the Squall Hammer (side B). This move is just annoying really. If you can punish it, do it. I really don't even care about this move since it really doesn't get anything done. Anyways, chances are, they'll be going for the grab. Do whatever you have to do to punish the grab attempt. You could time an Fsmash if they're really stupid (not recommended you attempt more than once or twice). Or you could time a spotdodge (but again, don't do this too often or they'll simply wait for the dodge to be up and then you're in a world of chaingrabbing pain. Also note that if you spotdodge a Squall Hammer it's still going to hit you. They can mindgame you in this way.). What I like to do after these options are too predictable is A) jump away and camp moar B) Space a move with decent range and little lag. Bair might work here if you do it straight from the jump. If you can desynch them, go into Nana **** mode.
(If you can't/don't want to outcamp them) You'll have to approach a little sometimes. Fireballs never KO'd anyone (barring gimps).
2. Most Ice Climbers tend to abuse their Blizzard for defensive purposes. While it is a good move that can do a LOT of damage (like 30%) if you get caught in the middle of it, it is VERY laggy and punishable. Your job is to bait one. Stick to the air. Use Bairs to try and poke them, but don't leave yourself open (rising Bairs are safer). Eventually they will use Blizzard instead of going for grabs. Blizzard will beat out Bairs or other pokes. Which is why you watch their pattern and wait for it. When you see the Blizzard, punish it by shooting a fireball through it, going over it and Dairing them (which might desynch... Nana ****!), or waiting till it ends and squeezing a quick attack in right after. If you you can get a Dthrow off, you can combo one of them, making the damage meters of the two unequal, making it easier to desynch.
3. If you do get grabbed, button mash VERY FAST and hope for the best. You can get a "get out of jail free" ticket if your % is low enough. You can also surprise SDI the Nana spike chaingrab and cause them to miss on the regrab, and sometimes it avoids the forced get up.
IN summation: Camp/Bait > Punish > Nana **** > Gimp/KO
STAGES: Battlefield is good against these guys. You can run around on the platforms all day, while shooting fireballs or popping down for a quick Bair, etc. It's actually really fun to fight Ice Climbers on this stage for some reason.
Don't go to FD. Period. Also be hesitant to go to Smashville.
Hope that helps. I don't actually use Mario, but I do play against a LOT of Ice Climbers. It's actually a pretty fun game to play against once you know how they roll. If your going to use a different character, you should switch to Marth or Zelda or ZZS. The same principles apply, just use the right moves.
Massive johns on his end.
