I am not sure what playstyle you use, but my memory serves to tell me that the Ice Climbers have a strong defense and offense laterally, but that they struggle to maintain or resist pressure for extended periods without a successful, launching hit. They must rapidly alternate between camping and retreating while on the defense, and between camping and advancing while on the attack. Therefore, I believe the key to be baiting an ill-timed repulsive effort when momentum is on your side, and playing patiently against an aggressive Ice Climbers player, waiting for those instances where the Ice Climbers are forced to move in order to gain/retain their advantage (it does not help them that there is something of a lag in the follower's response to inputs for the leader, tempting the Ice Climber's player to make minimal usage of shields in high-intensity situations ). Their weakness is a reliance on regular adjustment to their position to their position, combined with a necessity for easily distinguishable defensive/offensive behaviors. My knowledge of Brawl gameplay is quite rusty, but I hope this helps you.