Not many people might need this, but I have a strategy that works decent for Chapter 1 Saturn:
Lineup: Ninja Frog Cat, Dark Cat, Brah Cat, Lollycat/Panties Cat (Worker Cat Level Up Sm), Whale Cat, Rover Cat Mk II, Macho Leg Cat, Surfer Cat, and 2 anti-red units with area attack (Mine were Power Cutter Cat and Crazed Yuki).
Don't focus on upgrading the worker cat when you begin the stage. Keep in mind that LeMurr will approach the base faster than the group of One Horns; when the LeMurr gets close to your base, send out 1 of each anti-alien unit (1 Rover, 1 Macho Leg, 1 Surfer). Gradually send out more anti-alien units until LeMurr gets knocked back behind the group of One Horns. Once that happens, spam your cheap anti-red units (Ninja, Dark Cat, Whale, and Power Cutter if you have it) while simultaneously sending out an anti-alien unit in the mix. When a One Horn dies, spam every unit while upgrading the worker cat.
Note: Regular Cats and Special Cats in this lineup have to be at least level 20. My Surfer Cat was Level 5, Power Cutter was Level 16, and Crazed Yuki was Level 4.