Before the Boss
As soon as the stage begins, a One Horn is sent out. Ginger Snache joins the fun soon after. From there, after about 15 seconds, a Teacher Bear and Ginger Snache appear, with a third and fourth Ginger Snache appearing a few seconds later.
With the fourth Ginger Snache, Olympienne Cat appears to crush you, or die trying! After about 45 seconds, a Celeboodle and H. Nah come out. From there, more Celeboodles, H. Nahs, and Ginger Snaches appear to support the boss until the level ends.
What you want to do is use Paris cat and Bahamut to overpower the enemies. Raise the Worker Cat to level 3, and spam Eraser and Crazed Wall. Bring in Paris Cat and Crazed Sexy Legs when you can afford them. Dancer Cat acts as an attack support and can be replaced by other long-ranged attackers such as Drama Cats or Kasa Jizo.
When Olympienne Cat attacks, the One Horn should be almost dead. Use its money to send in a Bahamut and raise the Worker Cat to level 4. From there, just keep spamming Paris, Eraser, and Crazed Wall. If you can get the Worker Cat to level 5, start spamming Manic Mohawk.
Use the money from defeated enemies to summon Holy Valkyrie, Ururun, and more Dancer Cats. Spam Mohawk at the end of the level along with your other meatshields, and you should win.