Many say that stradegy is key. Over time as you play VF4 you get a feel for it. Some charge attacks (hold P or K down longer than a tap) lead your opponent closer to a wall, breakable or not it hurts more when you hit the wall or after it breaks, you may fall out of the ring ("Ring Out"). I often see people have an opponent in either mid air close to a wall or cornered against one. It often doesn't click in peoples head to utilize the arena. It's not cheap to slam someone into a wall, it is overdoing it if that's all you do though. If you are playing as kage for an example, you can footlaunch a opponent ( I don't know if it matters how big the opponent is ex: if a fighter like pai goes higher in the air than Jeffery) you can knee them and do a 3 hit punch string ( p, p, p fast) then kick you will have your opponent against the wall (if you started the combo in the center of the ring) So smack them against it a few times to score extra damage. Another is Sarah's high launch kick and then her kickflip rotation and slam! into the wall (if you started the combo closer to a wall) Wall juggles seem to work best for me on the unbreakable wall levels. Only use this stradegy, well it's not a stradegy but a suddgestion, Game on and remember, the walls are there or not there for a reason. Good luck!