The stage begins with a Le'boin and B.B.Bunnies spawning. When the enemy base is damaged, 3 Kiss and Koi will spawn in short order, followed by a One Horn, supported by peons. The main problem is that the Kiss and Kois are stacked, making it extremely hard to get many hits off on them.
At the start, kill off the Le'boin and the Kang Roos with Crazed Whale and Macho Leg and some meatshielding while you upgrade your wallet. Let them progress to the enemy base and trigger the boss wave without sending anything else out. Wait for them to die and lure Kiss and Koi close to your base and spam everything. Keep spamming and you should win.