The stage starts off by spawing The Face (Floating) with a large group of Pigeon de Sable. Then slowly it will spawn Kory, Dober P.D and a second wave of The Face constantly for a while. The spawning of Dober P.D will decrease but Kory will continue to be spawned through the game at a constant speed.
First let the group of Pigeon de Sable come near to your base before stacking a few meatshields to spawn C. Sexy Legs and Paris. Then spam upgrade your Wallet to Level 5/6. Next, constantly spam King Dragon, C. Dragon, C. Sexy Legs and Paris through out the entire game. Do not spawn meatshields anymore as they just increase the range of both Dober P.D and Kory. When nothing is blocking the way to The Face, spam Butterfly to increase damage output done onto The Face before the next set of Kory and Dober P.D arrive. A.Bahamut can be used to kill Kory and damage or kill Dober P.D and The Face if lucky. Rinse and repeat until you win the level.
Strategy 2 by HushT (ft. anti-shockwave)
All you really need for this stage is any anti shockwave cat. This could be something like Cat Machine Mk3, Gao, or Octopus Cat. I personally use octopus cat since it is cheap, relatively spamable, and weakens/resists floating. (Good for The Face and Pigeons)
Line up: Crazed Cat, Crazed Wall, Paris, Crazed Sexy Legs, Octopus Cat, and A. Bahamut. Any thing that will do good damage will speed this up.
Start of by spamming Octopus Cat and C. Sexy Legs to kill the Pigeons. After that just spam meatsheilds and Paris/Dragon. Everything will be protected from Kory/Dober P.D by Octopus Cat. When The Face starts his attack animation, send out A. Bahamut to kill everything.