This is one of the levels where Banner Cat can really shine as her weaken will help you keep them in control and her higher proc rates and short recharge time can make them weaken the enemies forever. Bring any anti-metal cat and critical hitters as well, as you will need them (However,Tesalan Pasalan isn't useful here due to the high amount of peons in the way).
Bring 4-5 meatshields. Fill the remaining slots with proccers and critters. Bring cat CPU. Stall the metal one horn and the metal doges for money. When you hit the base, lure the sir metal seal to your base, then turn on cat CPU. If this is done correctly, you will never run out of money, and win the stage.
If the strategy doesn’t work, upgrade your cats and try again.