Prepare for a battle of great stalling.
The main problem is the Bore shredding your anti-black units, but this is only a problem if you have never faced a Bore before. After killing the Bore, you should be able to destroy the base on 1/2 star difficulties. On 3 stars, just stall and chip down/kill the Gory Grooms while managing the bore with anti-red units. I used Weightlifter Cat and it was really good. Having multiple stacked up can do a really good job at mowing down the black enemies and damaging the Bore, and also protecting the strong units.