After damaging the base, Sleipnir, Angelic Gory and Zory will spawn alongside some peons. The peons will keep spawning at a fixed rate. Soon after, 2 Chickful As will spawn. After enough enemies are defeated, Zir Zeal will appear, possibly the biggest threat of the stage.
Since you have to complete this stage in order to go to the hidden stage (in THE MOON), you will have to arrange a lineup to make it through both stages.
The general strategy for this stage is to stall the Hippoes to build enough money and take on Sleipnir and the Chickful As. Zir Zeal is able to burrow and go through your defenses just like any other Zombie enemy, but what makes him dangerous is the fact that he will spawn after your units get pushed back by the Gories, so he will most likely emerge by the side of your base. However, you can the fire Cat Cannon to interrupt Zir Zeal as he goes down.
Strategy 1 (ft. Evangelion units)
This strategy involves specific Uber Rare units, some of them currently unavailable.
Strategy notes for this stage:
- Cameraman Cat and Seafarer Cat work as both damage dealers and meatshields.
- Manic Macho Legs will be useful to help clear the small peons.
- Can Can Cat can be replaced by Luxury Bath Cat as it outranges Corrupted Moneko and has a good damage output.
- NERV Moon has an ability affecting both Zombies and Red enemies, making it very useful in both stages.
At the start of the stage, level up the Worker Cat twice and spawn a Ramen Cat, he will stop the first Gabriel, keep one or two Ramen Cats (depending on level) at all times and max out the Worker. Once the Heavenly Hippoes are dealt with, spam everything except the NERV Moon.
Try to hold your position once the boss come out of the base. When Zir Zeal comes out, try to use the Cat Cannon to interrupt his burrowing animation. If you fail, spawn the NERV Moon to take care of Zir Zeal.
Both Orbital Platform Armageddon and the NERV Moon outrange Angelic Sleipnir and have the Zombie Killer ability, so once you eliminate Zir Zeal for good nothing should stop you.
To be continued in the next stage...