This is a Exam to test you that you can be superhero CatCatMan or not.
First 4 Stages are about 4 different type or catcatgun logic, player will be tested to pass the goal, also learn how to use catcatgun. After that, the final exam / mission will show up, player can join that and feel how Catcatman face undead E enemy and complete the impossible mission in darkness.