Start off by upgrading your wallet to level 2 or 3. When the 7 Iron Claw Xs spawn, start spamming cheap meatshields and some of your long range attackers. When your cat cannon is ready, make sure all of the Iron Claw Xs have fell in line, then shoot the cannon so that they all become synced. As long as they never get out of sync, this level should be even easier than the first. To prevent this, you probably want to have area attackers, and not single-target attackers like King Dragon. You will also want to make sure you have a long-distance SOL special/uber by the time the Pigeon de Sables come out, so that they don't wipe out your meatshield stacks.
At least four meatshields are needed to get in the way of the Iron Claw's single target attacks. Use Dragon Cat, Crazed Dragon, Drama Cats, Paris, and any other long-range attackers you have to chip away at the Iron Claw's health. An anti-black unit or two can be used take out the Doge Darks for easy money.
Lineup: Li'l Macho Cat, Crazed Macho Cat, Mohawk Cat, Wall Cat, Crazed Wall Cat, Ramen Cat, Jiangshi Cat, Jamiera Cat, and 2 long-range attackers: Ururun Cat, The Peach Devils (recommend main attackers >410 range to out-range the Iron Claw).
Battle Items: Rich Cat and Cat CPU.
At first , turn off the Cat CPU , spam Ramen Cat and some Wall to block and kill the Doge Darks. When you have enough money and The Iron Claws is near your base ( don't let them touch your base ) , turn on the Cat CPU and just see what 8 meatshields can do .