It starts with The Face spawning at the start. Then 4 waves of enemies will come out in swarms:
There is a delay between each wave allowing you some time to defeat the wave before the next one comes out. The Face mostly serves as a barrier and deterrent against knockback and to block your cats from advancing until the waves are defeated.
After that, Li'l Bun Buns will come out. Buy your strongest and fastest cats, protecting them with meatshields.
When you beat the Li'l Bun Buns, Zackie Pengs will come out. Spam your meatshields and your strong cats again. Zackie Pengs attack very fast and deal much more damage than many other enemies so spam your Cow Cats / Giraffe Cats to help manage them. They will die quickly and/or protect them with your meatshields.
When another Li'l Bun Bun comes, spam your meatshields until you have saved enough money to buy a strong cat like Bahamut Cat etc. Use this to attack Li'l Bun Bun, with protection from your meatshields or Li'l Bun Bun will destroy your meatshields and defeat your base.
After that, the Face isn't much of a problem, so the hard part is over. Onward to victory!
Strategy 2 (4 star)
Note: You can replace Weedwacker with Psychocat if he has zombie targeting talent.
Send Zamboney out so that it will force the Zrocos to burrow. Try to time it so that it will not be in range of The Face though it isn't as important if that happens since Zamboney can survive 2-3 chomps. Once the Zrocos starts getting close to your base, start summoning your meatshields, Li'l Flying Cat, and Weedwacker to kill them. Li'l Flying Cats serve as your close combat AoE damager while Weedwacker will freeze any Zrocos that starts getting close.
When the Li'l Bun Buns start coming out, immediately start summoning Cameraman Cat and some Sanzo Cat to deal with them and stop summoning Li'l Flying Cat and Weedwacker Cat. Cameraman serves as dual purpose of meatshield, damage dealer, and clean-up for any remaining Zrocos that you failed to kill before they arrived while Sanzo serves to as support to slow down the Li'l Bun Buns down to a crawl so they are easier to manage.
Zackie Pengs will arrive later on, start summoning Li'l Flying Cat and Weedwacker Cat again and stop with Camerman Cat and Sanzo Cat once the Li'l Bun Buns are dead (Cameraman Cat isn't terrible against them but doesn't have Zombie Kill).
A second wave of Li'l Bun Buns will arrive, probably while you are still trying to kill the Zackie Pengs. Add Cameraman Cat and some Sanzo Cats in the mix. This is the last wave. Once you clear out this wave, no more enemies will appear. You only need to send out Cameraman Cat and Awakened Bahamut to finish the Face.
If possible try to keep 4500 in reserve just in case things start getting dicey so that you can summon Awakened Bahamut to give you more breathing room, preferably if the enemies are lined up or if you are dealing with the second wave of Li'l Bun Buns. Keep in mind that Bahamut will later on get killed by The Face.