Once the peons are killed, a wave of Li'l Bun Bun comes out, and you have to stall the Li'l Bun Buns until their spawn rate decreases.
After that nothing appears.
A standard anti-floating line-up will work, including Cameraman Cat, Sadako Cat, Butterfly Cat, Sanzo Cat, Angry Deliquent Cat, and Warlock & Pierre (the anti-Alien/Floating version). Fill out the rest with meatshields and Ubers or standard heavy hitters.
The level starts out with some trash to allow you to build money, send out meatshields and Cameraman Cat. Some Brollows will come out - your Cameraman Cats should be able to hold them. If you can build up enough money, deploy Warlock & Pierre. After this it's just a matter of spamming all your other anti-floating cats and Ubers or heavy-hitters.